SlideShare a Scribd company logo
Delivering emergency medical services:
Research, theory, and application
Laura Albert
Industrial & Systems Engineering
University of Wisconsin-Madison
laura@engr.wisc.edu
punkrockOR.com
@lauraalbertphd
1
This work was in part supported by the U.S. Department of the Army under Grant Award Number W911NF-10-1-0176
and by the National Science Foundation under Award No. 1054148, 1444219, 1541165.
The road map
• How do emergency medical service (EMS) systems work?
• How do we know when EMS systems work well?
• How can we improve how well EMS systems work?
• Where is EMS search in operations research going?
• Where do they need to go?
2
Collaborators
Maria Mayorga
North Carolina State University
Students
Sardar Ansari
Ben Grannan
Soovin Yoon
3
One sentiment in the 1960s in the US
“If we can land a man on the moon…”
...why can't we attack fundamental societal problems using
math and operations research?
4
OR in EMS, fire & policing
5
The President’s
Commission on Law
Enforcement and the
Administration of Justice
(1965)
Al Blumstein chaired the
Commission’s Science
and Technology Task
Force (CMU)
Richard Larson did
much of the early
work (MIT)
1972
1972
A golden age of public safety research began
in the 1960s
• New York City / RAND Institute Collaboration
• Between 1963 – 1968, fire alarms in NYC increased 96% while
operating expenses remained the same
• New York City used simulation for the first time!
• The research was put into practice
• Public safety research applications were influential and
productive in the field of operations research
• Queueing, integer programming, simulation, data analytics
• Many applied operations research papers appeared in the
best journals
• The research won major awards (Lanchester, Edelman,
NATO Systems Science Prize)
6
Early urban operations research models
7
Set cover / maximum cover models
How can we “cover” the maximum
number of locations with
ambulances?
Church, R., & ReVelle, C. (1974). The maximal covering
location problem. Papers in regional science, 32(1),
101-118.
Markov models
How many fire engines should we send?
Swersey, A. J. (1982). A Markovian decision model for deciding how
many fire companies to dispatch. Management Science, 28(4), 352-
365.
Analytics
How far will a fire
engine travel to a call?
Kolesar, P., & Blum, E. H.
(1973). Square root laws
for fire engine response
distances. Management
Science, 19(12), 1368-1378.
Hypercube queueing models
What is the probability that our first choice
ambulance is unavailable for this call?
Larson, R. C. (1974). A hypercube queuing model for facility location
and redistricting in urban emergency services. Computers &
Operations Research, 1(1), 67-95.
Anatomy of a 911 call
Response time
Service provider:
Emergency 911 call
Unit
dispatched
Unit is en
route
Unit arrives
at scene
Service/care
provided
Unit leaves
scene
Unit arrives
at hospital
Patient
transferred
Unit returns
to service
8
Response time from the patient’s point of view
EMS design varies by community:
One size does not fit all
9McLay, L.A., 2011. Emergency Medical Service Systems that Improve Patient Survivability. Encyclopedia of Operations Research in the area of
“Applications with Societal Impact,” John Wiley & Sons, Inc., Hoboken, NJ (published online: DOI: 10.1002/9780470400531.eorms0296)
Fire and EMS vs. EMS
Paid staff vs. volunteers
Publicly run vs. privately run
Emergency medical technician
(EMT) vs. Paramedic (EMTp)
Mix of vehicles
Ambulance location,
relocation, and relocation
on-the-fly
Mutual aid
Performance standards come from the
National Fire Protection Agency (NFPA)
• NFPA 1710 guidelines for departments with paid staff
• 5 minute response time for first responding vehicle
• 9 minute response time for first advanced life support vehicle
• Must achieve these goals 90% of the time for all calls
• Similar guidelines for volunteer agencies in NFPA 1720 allow
for 9-14 minute response times
• Guidelines based on medical research for cardiac arrest
patients and time for structural fires to spread
• Short response times only critical for some patient types:
cardiac arrest, shock, myocardial infarction
• Most calls are lower-acuity
• Many communities use different response time goals
10
Operationalizing recommendations when
sending ambulances to calls
Priority dispatch:
… but which ambulance when there is a choice?
11
Type Capability Response Time
Priority 1
Advanced Life Support (ALS) Emergency
Send ALS and a fire engine/BLS
E.g., 9 minutes
(first unit)
Priority 2
Basic Life Support (BLS) Emergency
Send BLS and a fire engine if available
E.g., 13 minutes
Priority 3
Not an emergency
Send BLS
E.g., 16 minutes
Performance standards
National Fire Protection Agency (NFPA) standard yields a
coverage objective function for response times
Most common response time threshold (RTT):
9 minutes for 80% of calls
• Easy to measure
• Intuitive
• Unambiguous
12
Response times vs. cardiac arrest survival
13
CDF of
calls for
service
covered
Response time (minutes) 9
80%
What is the best response time threshold?
• Guidelines suggest 9 minutes
• Medical research suggests ~5 minutes
• But this would disincentive 5-9 minute responses
14
Responses
no longer
“count”
What is the best response time threshold?
• Guidelines suggest 9 minutes
• Medical research suggests ~5 minutes
• But this would disincentive 5-9 minute responses
• Which RTT is best for design of the system?
15
What is the best response time threshold
based on retrospective survival rates?
Decision context is locating and dispatching ALS ambulances
• Discrete optimization model to locate ambulances *
• Markov decision process model to dispatch ambulances
16
* McLay, L.A. and M.E. Mayorga, 2010. Evaluating Emergency Medical Service Performance Measures. Health Care
Management Science 13(2), 124 - 136
Survival and dispatch decisions
17
Across different ambulance
configurations
Across different call
volumes
McLay, L.A., Mayorga, M.E., 2011. Evaluating the Impact of Performance Goals on Dispatching Decisions in
Emergency Medical Service. IIE Transactions on Healthcare Service Engineering 1, 185 – 196
Minimize un-survivability when altering dispatch decisions
Ambulance Locations, N=7
Best for patient survival / 8 Minute RTT
= one ambulance
= two ambulances
McLay, L.A. and M.E. Mayorga, 2010. Evaluating Emergency Medical Service
Performance Measures. Health Care Management Science 13(2), 124 - 136
Suburban area –>
(vs. rural areas)
<– Interstates
18
Ambulance Locations, N=7
10 Minute RTT
= one ambulance
= two ambulances
McLay, L.A. and M.E. Mayorga, 2010. Evaluating Emergency Medical Service
Performance Measures. Health Care Management Science 13(2), 124 - 136
19
Ambulance Locations, N=7
5 Minute RTT
= one ambulance
= two ambulances
McLay, L.A. and M.E. Mayorga, 2010. Evaluating Emergency Medical Service
Performance Measures. Health Care Management Science 13(2), 124 - 136 20
Dispatching models
21
Optimal dispatching policies
using Markov decision process models
911 call
Unit
dispatched
Unit is en
route
Unit arrives
at scene
Service/care
provided
Unit leaves
scene
Unit arrives
at hospital
Patient
transferred
Unit returns
to service
Determine which
ambulance to send based
on classified priority
Classified
priority
(H or L)
True
priority
HT or LT
22
Information changes over the course of a call
Decisions made based on classified priority.
Performance metrics based on true priority.
Classified customer risk
Map Priority 1, 2, 3 call types to high-priority (𝐻𝐻) or low-priority (𝐿𝐿)
Calls of the same type treated the same
True customer risk
Map all call types to high-priority (𝐻𝐻𝑇𝑇) or low-priority (𝐿𝐿𝑇𝑇)
Optimal dispatching policies
using Markov decision process models
Optimality equations:
𝑉𝑉𝑘𝑘 𝑆𝑆𝑘𝑘 = max
𝑥𝑥𝑘𝑘∈𝑋𝑋(𝑆𝑆𝑘𝑘)
𝐸𝐸 𝑢𝑢𝑖𝑖𝑖𝑖
𝜔𝜔
𝑥𝑥𝑘𝑘 + 𝑉𝑉𝑘𝑘+1 𝑆𝑆𝑘𝑘+1 𝑆𝑆𝑘𝑘, 𝑥𝑥𝑘𝑘, 𝜔𝜔
Formulate problem as an undiscounted, infinite-horizon,
average reward Markov decision process (MDP) model
• The state 𝒔𝒔𝒌𝒌 ∈ 𝑆𝑆 describes the combinations of busy and free ambulances.
• 𝑋𝑋(𝒔𝒔𝑘𝑘) denotes the set of actions (ambulances to dispatch) available in state 𝒔𝒔𝒌𝒌.
• Reward 𝑢𝑢𝑖𝑖𝑖𝑖
𝜔𝜔 depend on true priority (random).
• Transition probabilities: the state changes when (1) one of the busy servers
completes service or (2) a server is assigned to a new call.
Select
best
ambulance
to send
Value in
current
state
Values in
(possible)
next states
(Random)
reward based
on true patient
priority
Under- or over-prioritize
• Assumption:
No priority 3 calls are truly high-priority
Case 1: Under-prioritize with different classification accuracy
Case 2: Over-prioritize
Pr1 Pr2 Pr3
Pr1 Pr2 Pr3
HT
HT
Pr1 Pr2 Pr3
HT
Pr1 Pr2 Pr3
HT
Informational
accuracy captured by:
𝛼𝛼 =
𝑃𝑃 𝐻𝐻𝑇𝑇 𝐻𝐻
𝑃𝑃(𝐻𝐻𝑇𝑇|𝐿𝐿)
24
Classified high-priority
Classified low-priority
Improved accuracy
Structural properties
RESULT
It is more beneficial for an ambulance to be idle than busy.
RESULT
It is more beneficial for an ambulance to be serving closer
patients.
RESULT
It is not always optimal to send the closest ambulance, even for
high priority calls.
Coverage
0 10 20 30 40 50
0.405
0.41
0.415
0.42
0.425
0.43
0.435
0.44
0.445
α
Expectedcoverage
Optimal Policy, Case 1
Optimal Policy, Case 2
Closest Ambulance
26
Better accuracy
Low and high priority calls
Conditional probability that the closest unit is dispatched given
initial classification
High-priority calls Low-priority calls0 10 20 30 40 50
0.98
0.985
0.99
0.995
1
1.005
α
Proportionclosestambulanceisdispatched
Closest Ambulance
Optimal Policy, Case 1
Optimal Policy, Case 2
0 10 20 30 40 50
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
α
Proportionclosestambulanceisdispatched
Closest Ambulance
Optimal Policy, Case 1
Optimal Policy, Case 2
Classified high-priority Classified low-priority
27
Case 1 (𝛼𝛼 = ∞), Case 2 policies
High-priority calls
Case 2: First to send to high-priority calls
Station
1
2
3
4
Case 2: Second to send to high-priority calls
Station
1
2
3
4
Service can be improved via optimization of backup service and response to low-priority patients
Rationed for
high-priority calls
Rationed for low-
priority calls
28
Districting and location models
29
Ambulance response districts
How should we locate ambulances?
How should we design response districts around each ambulance?
• Multiple ambulances per station
• Ambulance unavailability (spatial queueing)
• Uncertain travel times / Fractional coverage
• Workload balancing: all ambulances do the same amount of work
30Ansari, S., McLay, L.A., Mayorga, M.E., 2016. A maximum expected covering problem for locating and dispatching servers.
Transportation Science, published online in Articles in Advance.
Spatial
queueing
model
Mixed integer
programming
model
Districting model
Mixed Integer Linear Program
max ∑𝑤𝑤∈𝑊𝑊 ∑𝑗𝑗∈𝐽𝐽 ∑𝑝𝑝=1
𝑠𝑠 ∑ 𝑚𝑚=1
min(𝑐𝑐 𝑤𝑤,𝑠𝑠−𝑝𝑝+1)
𝑞𝑞𝑗𝑗𝑗𝑗𝑗𝑗 1 − 𝑟𝑟 𝑚𝑚
𝑟𝑟 𝑝𝑝−1
𝜆𝜆𝑗𝑗
𝐻𝐻
𝑅𝑅𝑤𝑤𝑤𝑤 𝑧𝑧𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤
subject to
∑𝑝𝑝=1
𝑠𝑠 ∑ 𝑚𝑚=1
𝜅𝜅 𝑤𝑤𝑤𝑤
𝑧𝑧𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤 ≤ 1, 𝑗𝑗 ∈ 𝐽𝐽, 𝑤𝑤 ∈ 𝑊𝑊
∑𝑝𝑝=1
𝑠𝑠 ∑ 𝑚𝑚=1
𝜅𝜅 𝑤𝑤𝑤𝑤
𝑧𝑧𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤 ≤ 𝑦𝑦𝑤𝑤, 𝑗𝑗 ∈ 𝐽𝐽, 𝑤𝑤 ∈ 𝑊𝑊
∑𝑤𝑤∈𝑊𝑊 𝑥𝑥𝑤𝑤𝑤𝑤𝑤𝑤 = 1, 𝑗𝑗 ∈ 𝐽𝐽, 𝑝𝑝 = 1, … , 𝑠𝑠
∑𝑝𝑝=1
𝑠𝑠
𝑥𝑥𝑤𝑤𝑤𝑤𝑤𝑤 = 𝑦𝑦𝑤𝑤 , 𝑗𝑗 ∈ 𝐽𝐽, 𝑤𝑤 ∈ 𝑊𝑊
𝑥𝑥𝑤𝑤𝑤𝑤𝑤𝑤𝑤 = ∑𝑝𝑝=max 1,𝑝𝑝′−𝑐𝑐 𝑤𝑤+1
𝑝𝑝𝑝
∑ 𝑚𝑚=𝑝𝑝′−𝑝𝑝+1
𝜅𝜅 𝑤𝑤𝑤𝑤
𝑧𝑧𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤 ,
𝑗𝑗 ∈ 𝐽𝐽, 𝑤𝑤 ∈ 𝑊𝑊, 𝑝𝑝′
= 1, … , 𝑠𝑠
∑𝑤𝑤∈𝑊𝑊 𝑦𝑦𝑤𝑤 = 𝑠𝑠
𝑦𝑦𝑤𝑤 ≤ 𝑐𝑐𝑤𝑤, 𝑤𝑤 ∈ 𝑊𝑊
𝑟𝑟 − 𝛿𝛿 𝑦𝑦𝑤𝑤 ≤
∑𝑗𝑗∈𝐽𝐽 ∑𝑝𝑝=1
𝑠𝑠 ∑ 𝑚𝑚=1
𝜅𝜅 𝑤𝑤𝑤𝑤
𝜆𝜆𝑗𝑗
𝐻𝐻
+ 𝜆𝜆𝑗𝑗
𝐿𝐿
𝑞𝑞𝑗𝑗𝑗𝑗𝑗𝑗 1 − 𝑟𝑟 𝑚𝑚
𝑟𝑟 𝑝𝑝−1
𝜏𝜏𝑤𝑤𝑤𝑤 𝑧𝑧𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤
≤ 𝑟𝑟 + 𝛿𝛿 𝑦𝑦𝑤𝑤, 𝑤𝑤 ∈ 𝑊𝑊
𝑥𝑥𝑤𝑤𝑤𝑤𝑤𝑤 ≥ 𝑥𝑥𝑤𝑤𝑤𝑤𝑤, 𝑗𝑗 ∈ 𝐽𝐽, 𝑤𝑤 ∈ 𝑊𝑊, 𝑗𝑗′
∈ 𝑁𝑁𝑤𝑤𝑤𝑤
𝑦𝑦𝑤𝑤 ∈ 𝑍𝑍0
+
, 𝑤𝑤 ∈ 𝑊𝑊
𝑥𝑥𝑤𝑤𝑤𝑤𝑤𝑤 ∈ 0,1 , 𝑤𝑤 ∈ 𝑊𝑊, 𝑗𝑗 ∈ 𝐽𝐽, 𝑝𝑝 = 1, … , 𝑠𝑠
𝑧𝑧𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤 ∈ 0,1 , 𝑤𝑤 ∈ 𝑊𝑊, 𝑗𝑗 ∈ 𝐽𝐽, 𝑝𝑝 = 1, … , 𝑠𝑠, 𝑚𝑚 = 1, … , 𝑐𝑐𝑤𝑤
31
Every customer has all the priorities and the
number of assignments to a station is equal to
the number of servers located at that station
A customer location is not assigned to
a station more than once and no call
location is assigned to a closed station
Linking constraints
Balance the load amongst
the servers
Locate 𝑠𝑠 servers with no more than 𝑐𝑐𝑤𝑤 per
station
Expected coverage
Contiguous first priority districts
Binary and integrality
constraints on the variables
Parameters
• 𝐽𝐽: set of all customer (demand) nodes
• 𝑊𝑊: set of all potential station locations
• 𝑠𝑠: total number of servers in the system
• 𝜆𝜆𝑗𝑗
𝐻𝐻
(𝜆𝜆𝑗𝑗
𝐿𝐿
): mean high-priority (low-priority)
call arrival rates from node 𝑗𝑗
• 𝜆𝜆: system-wide total call arrival rate
• 𝜏𝜏𝑤𝑤𝑤𝑤: mean service time for calls originated
from node 𝑗𝑗 and served by a server from a
potential station 𝑤𝑤.
• 𝜏𝜏: system-wide mean service time
• 𝑐𝑐𝑤𝑤: capacity of station 𝑤𝑤
32
• 𝑟𝑟: system-wide average server utilization
• 𝑃𝑃𝑠𝑠: loss probability (probability that all 𝑠𝑠
servers are busy)
• 𝑅𝑅𝑤𝑤𝑤𝑤: expected proportion of calls from 𝑗𝑗
that are reached by servers from station 𝑤𝑤
in nine minutes
• 𝑞𝑞𝑗𝑗𝑗𝑗𝑗𝑗: correction factor for customer 𝑗𝑗's 𝑝𝑝th
priority server at which there are 𝑚𝑚 servers
located.
• 𝑁𝑁𝑤𝑤𝑤𝑤: set of demand nodes that are
neighbors to 𝑗𝑗 and are closer to station 𝑤𝑤
than 𝑗𝑗.
Decision variables
• 𝑦𝑦𝑤𝑤 = number of servers located at station 𝑤𝑤, 𝑤𝑤 ∈ 𝑊𝑊.
• 𝑧𝑧𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤= 1 if there are 𝑝𝑝 − 1 servers located at stations that node 𝑗𝑗 prefers over 𝑤𝑤 and there
are 𝑚𝑚 servers located at station 𝑤𝑤, 𝑤𝑤 ∈ 𝑊𝑊, 𝑗𝑗 ∈ 𝐽𝐽, 𝑝𝑝 = 1, … , 𝑠𝑠, 𝑚𝑚 = 1, … , 𝑐𝑐𝑤𝑤 and 0 otherwise.
• 𝑥𝑥𝑤𝑤𝑤𝑤𝑤𝑤= 1 if 𝑝𝑝′
< 𝑝𝑝 < 𝑠𝑠 − 𝑝𝑝𝑝𝑝 where are 𝑝𝑝′
is the number of servers located at stations that
node 𝑗𝑗 prefers over 𝑤𝑤, and 𝑝𝑝′′
is the number of servers located at stations that node 𝑗𝑗 prefers
less than 𝑤𝑤, 𝑤𝑤 ∈ 𝑊𝑊, 𝑗𝑗 ∈ 𝐽𝐽, 𝑝𝑝 = 1, … , 𝑠𝑠, and 0 otherwise.
Results
RESULT
The Base model that does not maintain contiguity or a balanced
load amongst the ambulances is NP-complete.
• reduction from k-median
RESULT
The first priority response districts for the Base model are
contiguous if there is no more than one ambulance per station.
RESULT
Identifying districts that balance the workload is NP-complete.
• reduction from bin packing
RESULT
Reduced model to assign only the top 𝑠𝑠′ ≤ 𝑠𝑠 ambulances
• Not trivial, allows model to scale up to have many ambulances
33
Hanover County: example
First priority districts for the base model
• Base Model: no workload balancing or contiguity constraints
Model with workload balancing but no
contiguity constraints
• First Priority Districts for one time period
First priority districts may be different if we
balance the workload
• Workload balancing
• Contiguous first priority districts
Two ambulances
Coordinating multiple types of vehicles is not
intuitive due to double response
• Not intuitive how to use multiple types of vehicles
• ALS ambulances / BLS ambulances (2 EMTp/EMT)
• ALS quick response vehicles (QRVs) (1 EMTp)
• Double response = both ALS and BLS units dispatched
• Downgrades / upgrades for Priority 1 / 2 calls
• Who transports the patient to the hospital?
• Research goal: operationalize guidelines for sending vehicle
types to prioritized patients
• (Linear) integer programming model for a two vehicle-type
system: ALS Non-transport QRVs and BLS ambulances
38
The more ALS QRVs in use, the better the
coverage
39
Application in a real setting: the results were
better than anticipated
40
Achievement Award Winner for Next-Generation Emergency Medical Response
Through Data Analysis & Planning (Best in Category winner), National
Association of Counties, 2010.
McLay, L.A., Moore, H. 2012. Hanover County Improves Its Response to Emergency Medical 911 Calls. Interfaces 42(4),
380-394.
Where do EMS systems need to go?
41
EMS = Prehospital care
Operations Research
• Efficiency
• Optimality
• Utilization
• System-wide performance
Healthcare
• Efficacy
• Access
• Resources/costs
• “Patient centered outcomes”
42
Healthcare
Transportation
Public sector
Common ground?
More thoughts on patient centered outcomes
Operational measures used to
evaluate emergency departments
• Length of stay
• Throughput
Increasing push for more health
metrics
• Disease progression
• Recidivism
Many challenges for EMS modeling
• Health metrics needed
• Information collected at scene
• Equity models a good vehicle for
examining health measures
(access, cost, efficacy)
43
Healthcare
Transportation
Public sector
Patient centered outcomes
44
EMS response during/after extreme events
depends on critical infrastructure
45
EMS service largely dependent on other
interdependent systems and networks
Decisions may be very different during
disasters
• Ask patients to wait for service
• Patient priorities may be dynamic
• Evacuate patients from hospitals
• Massive coordination with other
agencies (mutual aid)
Two main research streams exist:
1. Normal operations
2. Disaster operations
More guidance needed for “typical”
emergencies and mass casualty
events
E.g., Health risks during/after
hurricanes:
• Increased mortality, traumatic
injuries, low-priority calls
• Carbon monoxide poisoning,
Electronic health devices
* Caused by power failures
Thank you!
46
1. McLay, L.A., Mayorga, M.E., 2013. A model for optimally dispatching ambulances to emergency calls with classification errors in patient
priorities. IIE Transactions 45(1), 1—24.
2. McLay, L.A., Mayorga, M.E., 2011. Evaluating the Impact of Performance Goals on Dispatching Decisions in Emergency Medical Service. IIE
Transactions on Healthcare Service Engineering 1, 185 – 196
3. McLay, L.A., Mayorga, M.E., 2014. A dispatching model for server-to-customer systems that balances efficiency and equity. To appear in
Manufacturing & Service Operations Management, doi:10.1287/msom.1120.0411
4. Ansari, S., McLay, L.A., Mayorga, M.E., 2015. A maximum expected covering problem for locating and dispatching servers. To appear in
Transportation Science.
5. Kunkel, A., McLay, L.A. 2013. Determining minimum staffing levels during snowstorms using an integrated simulation, regression, and reliability
model. Health Care Management Science 16(1), 14 – 26.
6. McLay, L.A., Moore, H. 2012. Hanover County Improves Its Response to Emergency Medical 911 Calls. Interfaces 42(4), 380-394.
7. Leclerc, P.D., L.A. McLay, M.E. Mayorga, 2011. Modeling equity for allocating public resources. Community-Based Operations Research: Decision
Modeling for Local Impact and Diverse Populations, Springer, p. 97 – 118.
8. McLay, L.A., Brooks, J.P., Boone, E.L., 2012. Analyzing the Volume and Nature of Emergency Medical Calls during Severe Weather Events using
Regression Methodologies. Socio-Economic Planning Sciences 46, 55 – 66.
9. McLay, L.A., 2011. Emergency Medical Service Systems that Improve Patient Survivability. Encyclopedia of Operations Research in the area of
“Applications with Societal Impact,” John Wiley & Sons, Inc., Hoboken, NJ (published online: DOI: 10.1002/9780470400531.eorms0296)
10. McLay, L.A. and M.E. Mayorga, 2010. Evaluating Emergency Medical Service Performance Measures. Health Care Management Science 13(2),
124 - 136
laura@engr.wisc.edu
punkrockOR.com
@lauraalbertphd

More Related Content

Similar to Delivering emergency medical services:Research, theory, and application

NDGISUC2017 - Addressing Geographic Disparities in Access to Ambulance Services
NDGISUC2017 - Addressing Geographic Disparities in Access to Ambulance ServicesNDGISUC2017 - Addressing Geographic Disparities in Access to Ambulance Services
NDGISUC2017 - Addressing Geographic Disparities in Access to Ambulance ServicesNorth Dakota GIS Hub
 
National Strategy for Improving Outcomes for Sudden Cardiac Arrest in Singapore
National Strategy for Improving Outcomes for Sudden Cardiac Arrest in SingaporeNational Strategy for Improving Outcomes for Sudden Cardiac Arrest in Singapore
National Strategy for Improving Outcomes for Sudden Cardiac Arrest in Singaporezybernav
 
RuralEMS_Lewman_PosterPresentation2015
RuralEMS_Lewman_PosterPresentation2015RuralEMS_Lewman_PosterPresentation2015
RuralEMS_Lewman_PosterPresentation2015CPSKatie
 
234239034 emergency-priority-of-ambulabe
234239034 emergency-priority-of-ambulabe234239034 emergency-priority-of-ambulabe
234239034 emergency-priority-of-ambulabehomeworkping3
 
33TRANSITIONING FOURTEEN VOLUNTEER FIRE STATIONS INTO A COMBIN.docx
33TRANSITIONING FOURTEEN VOLUNTEER FIRE STATIONS INTO A COMBIN.docx33TRANSITIONING FOURTEEN VOLUNTEER FIRE STATIONS INTO A COMBIN.docx
33TRANSITIONING FOURTEEN VOLUNTEER FIRE STATIONS INTO A COMBIN.docxrhetttrevannion
 
33TRANSITIONING FOURTEEN VOLUNTEER FIRE STATIONS INTO A COMBIN.docx
33TRANSITIONING FOURTEEN VOLUNTEER FIRE STATIONS INTO A COMBIN.docx33TRANSITIONING FOURTEEN VOLUNTEER FIRE STATIONS INTO A COMBIN.docx
33TRANSITIONING FOURTEEN VOLUNTEER FIRE STATIONS INTO A COMBIN.docxgilbertkpeters11344
 
Kearns%20 iom%20csc it%20meeting%20jan%2015
Kearns%20 iom%20csc it%20meeting%20jan%2015Kearns%20 iom%20csc it%20meeting%20jan%2015
Kearns%20 iom%20csc it%20meeting%20jan%2015Randy Kearns
 
Chase presentation
Chase presentationChase presentation
Chase presentationReza Sadeghi
 
RT-GRID: Grid Computing for Radiotherapy
RT-GRID:  Grid Computing for RadiotherapyRT-GRID:  Grid Computing for Radiotherapy
RT-GRID: Grid Computing for RadiotherapyBarakaFundo1
 
Ascend Presentation
Ascend PresentationAscend Presentation
Ascend PresentationAirambulance
 
A multiperiod set covering location model for dynamic redeployment of ambulances
A multiperiod set covering location model for dynamic redeployment of ambulancesA multiperiod set covering location model for dynamic redeployment of ambulances
A multiperiod set covering location model for dynamic redeployment of ambulancesHari Rajagopalan
 
Idaho Mass Casualty Incident Response
Idaho Mass Casualty Incident ResponseIdaho Mass Casualty Incident Response
Idaho Mass Casualty Incident ResponseNick Nudell
 
Reduction of Call Abandonment Rate of Information Services Helpdesk at United...
Reduction of Call Abandonment Rate of Information Services Helpdesk at United...Reduction of Call Abandonment Rate of Information Services Helpdesk at United...
Reduction of Call Abandonment Rate of Information Services Helpdesk at United...amande1
 
Team Surgency
Team SurgencyTeam Surgency
Team SurgencyH4Diadmin
 
Mesh Goes to the Marathon
Mesh Goes to the MarathonMesh Goes to the Marathon
Mesh Goes to the MarathonErik Westgard
 
PA 2015 Telephone Triage A0 size
PA 2015 Telephone Triage A0 sizePA 2015 Telephone Triage A0 size
PA 2015 Telephone Triage A0 sizeHarry Misselbrook
 
Sabato Ems Studentlecture
Sabato Ems StudentlectureSabato Ems Studentlecture
Sabato Ems Studentlecturejsgehring
 
Riley_Courtney_ASPIRE_Poster
Riley_Courtney_ASPIRE_PosterRiley_Courtney_ASPIRE_Poster
Riley_Courtney_ASPIRE_PosterCourtney Riley
 

Similar to Delivering emergency medical services:Research, theory, and application (20)

NDGISUC2017 - Addressing Geographic Disparities in Access to Ambulance Services
NDGISUC2017 - Addressing Geographic Disparities in Access to Ambulance ServicesNDGISUC2017 - Addressing Geographic Disparities in Access to Ambulance Services
NDGISUC2017 - Addressing Geographic Disparities in Access to Ambulance Services
 
National Strategy for Improving Outcomes for Sudden Cardiac Arrest in Singapore
National Strategy for Improving Outcomes for Sudden Cardiac Arrest in SingaporeNational Strategy for Improving Outcomes for Sudden Cardiac Arrest in Singapore
National Strategy for Improving Outcomes for Sudden Cardiac Arrest in Singapore
 
Cardiac Arrest Strategy
Cardiac Arrest StrategyCardiac Arrest Strategy
Cardiac Arrest Strategy
 
RuralEMS_Lewman_PosterPresentation2015
RuralEMS_Lewman_PosterPresentation2015RuralEMS_Lewman_PosterPresentation2015
RuralEMS_Lewman_PosterPresentation2015
 
234239034 emergency-priority-of-ambulabe
234239034 emergency-priority-of-ambulabe234239034 emergency-priority-of-ambulabe
234239034 emergency-priority-of-ambulabe
 
33TRANSITIONING FOURTEEN VOLUNTEER FIRE STATIONS INTO A COMBIN.docx
33TRANSITIONING FOURTEEN VOLUNTEER FIRE STATIONS INTO A COMBIN.docx33TRANSITIONING FOURTEEN VOLUNTEER FIRE STATIONS INTO A COMBIN.docx
33TRANSITIONING FOURTEEN VOLUNTEER FIRE STATIONS INTO A COMBIN.docx
 
33TRANSITIONING FOURTEEN VOLUNTEER FIRE STATIONS INTO A COMBIN.docx
33TRANSITIONING FOURTEEN VOLUNTEER FIRE STATIONS INTO A COMBIN.docx33TRANSITIONING FOURTEEN VOLUNTEER FIRE STATIONS INTO A COMBIN.docx
33TRANSITIONING FOURTEEN VOLUNTEER FIRE STATIONS INTO A COMBIN.docx
 
Kearns%20 iom%20csc it%20meeting%20jan%2015
Kearns%20 iom%20csc it%20meeting%20jan%2015Kearns%20 iom%20csc it%20meeting%20jan%2015
Kearns%20 iom%20csc it%20meeting%20jan%2015
 
Chase presentation
Chase presentationChase presentation
Chase presentation
 
RT-GRID: Grid Computing for Radiotherapy
RT-GRID:  Grid Computing for RadiotherapyRT-GRID:  Grid Computing for Radiotherapy
RT-GRID: Grid Computing for Radiotherapy
 
Ascend Presentation
Ascend PresentationAscend Presentation
Ascend Presentation
 
Ascend Presentation
Ascend PresentationAscend Presentation
Ascend Presentation
 
A multiperiod set covering location model for dynamic redeployment of ambulances
A multiperiod set covering location model for dynamic redeployment of ambulancesA multiperiod set covering location model for dynamic redeployment of ambulances
A multiperiod set covering location model for dynamic redeployment of ambulances
 
Idaho Mass Casualty Incident Response
Idaho Mass Casualty Incident ResponseIdaho Mass Casualty Incident Response
Idaho Mass Casualty Incident Response
 
Reduction of Call Abandonment Rate of Information Services Helpdesk at United...
Reduction of Call Abandonment Rate of Information Services Helpdesk at United...Reduction of Call Abandonment Rate of Information Services Helpdesk at United...
Reduction of Call Abandonment Rate of Information Services Helpdesk at United...
 
Team Surgency
Team SurgencyTeam Surgency
Team Surgency
 
Mesh Goes to the Marathon
Mesh Goes to the MarathonMesh Goes to the Marathon
Mesh Goes to the Marathon
 
PA 2015 Telephone Triage A0 size
PA 2015 Telephone Triage A0 sizePA 2015 Telephone Triage A0 size
PA 2015 Telephone Triage A0 size
 
Sabato Ems Studentlecture
Sabato Ems StudentlectureSabato Ems Studentlecture
Sabato Ems Studentlecture
 
Riley_Courtney_ASPIRE_Poster
Riley_Courtney_ASPIRE_PosterRiley_Courtney_ASPIRE_Poster
Riley_Courtney_ASPIRE_Poster
 

More from Laura Albert

Optimization with impact: my journey in public sector operations research
Optimization with impact: my journey in public sector operations research Optimization with impact: my journey in public sector operations research
Optimization with impact: my journey in public sector operations research Laura Albert
 
Should a football team go for a one or two point conversion? A dynamic progra...
Should a football team go for a one or two point conversion? A dynamic progra...Should a football team go for a one or two point conversion? A dynamic progra...
Should a football team go for a one or two point conversion? A dynamic progra...Laura Albert
 
Volleyball analytics: Modeling volleyball using Markov chains
Volleyball analytics: Modeling volleyball using Markov chainsVolleyball analytics: Modeling volleyball using Markov chains
Volleyball analytics: Modeling volleyball using Markov chainsLaura Albert
 
2018 INFORMS Government & Analytics Summit Overview
2018 INFORMS Government & Analytics Summit Overview2018 INFORMS Government & Analytics Summit Overview
2018 INFORMS Government & Analytics Summit OverviewLaura Albert
 
Bracketology talk at the Crossroads of ideas
Bracketology talk at the Crossroads of ideasBracketology talk at the Crossroads of ideas
Bracketology talk at the Crossroads of ideasLaura Albert
 
Wicked problems in operations research
Wicked problems in operations researchWicked problems in operations research
Wicked problems in operations researchLaura Albert
 
Spring new educators orientation
Spring new educators orientationSpring new educators orientation
Spring new educators orientationLaura Albert
 
engineering systems: critical infrastructure and logistics
engineering systems: critical infrastructure and logisticsengineering systems: critical infrastructure and logistics
engineering systems: critical infrastructure and logisticsLaura Albert
 
Operations Research for Homeland Security and Beyond!
Operations Research for Homeland Security and Beyond!Operations Research for Homeland Security and Beyond!
Operations Research for Homeland Security and Beyond!Laura Albert
 
Discrete Optimization Models for Homeland Security and Disaster Management
Discrete Optimization Models for Homeland Security and Disaster ManagementDiscrete Optimization Models for Homeland Security and Disaster Management
Discrete Optimization Models for Homeland Security and Disaster ManagementLaura Albert
 
Should a football team run or pass? A linear programming approach to game theory
Should a football team run or pass? A linear programming approach to game theoryShould a football team run or pass? A linear programming approach to game theory
Should a football team run or pass? A linear programming approach to game theoryLaura Albert
 
Integer programming for locating ambulances
Integer programming for locating ambulancesInteger programming for locating ambulances
Integer programming for locating ambulancesLaura Albert
 
Screening Commercial Aviation Passengers in the Aftermath of September 11, 2001
Screening Commercial Aviation Passengers in the Aftermath of September 11, 2001Screening Commercial Aviation Passengers in the Aftermath of September 11, 2001
Screening Commercial Aviation Passengers in the Aftermath of September 11, 2001Laura Albert
 
Women in engineering luncheon presentation at CASE 2013 (IEEE conference on a...
Women in engineering luncheon presentation at CASE 2013 (IEEE conference on a...Women in engineering luncheon presentation at CASE 2013 (IEEE conference on a...
Women in engineering luncheon presentation at CASE 2013 (IEEE conference on a...Laura Albert
 
So you're thinking about graduate school in operations research, math, or eng...
So you're thinking about graduate school in operations research, math, or eng...So you're thinking about graduate school in operations research, math, or eng...
So you're thinking about graduate school in operations research, math, or eng...Laura Albert
 
Technical writing tips
Technical writing tipsTechnical writing tips
Technical writing tipsLaura Albert
 

More from Laura Albert (16)

Optimization with impact: my journey in public sector operations research
Optimization with impact: my journey in public sector operations research Optimization with impact: my journey in public sector operations research
Optimization with impact: my journey in public sector operations research
 
Should a football team go for a one or two point conversion? A dynamic progra...
Should a football team go for a one or two point conversion? A dynamic progra...Should a football team go for a one or two point conversion? A dynamic progra...
Should a football team go for a one or two point conversion? A dynamic progra...
 
Volleyball analytics: Modeling volleyball using Markov chains
Volleyball analytics: Modeling volleyball using Markov chainsVolleyball analytics: Modeling volleyball using Markov chains
Volleyball analytics: Modeling volleyball using Markov chains
 
2018 INFORMS Government & Analytics Summit Overview
2018 INFORMS Government & Analytics Summit Overview2018 INFORMS Government & Analytics Summit Overview
2018 INFORMS Government & Analytics Summit Overview
 
Bracketology talk at the Crossroads of ideas
Bracketology talk at the Crossroads of ideasBracketology talk at the Crossroads of ideas
Bracketology talk at the Crossroads of ideas
 
Wicked problems in operations research
Wicked problems in operations researchWicked problems in operations research
Wicked problems in operations research
 
Spring new educators orientation
Spring new educators orientationSpring new educators orientation
Spring new educators orientation
 
engineering systems: critical infrastructure and logistics
engineering systems: critical infrastructure and logisticsengineering systems: critical infrastructure and logistics
engineering systems: critical infrastructure and logistics
 
Operations Research for Homeland Security and Beyond!
Operations Research for Homeland Security and Beyond!Operations Research for Homeland Security and Beyond!
Operations Research for Homeland Security and Beyond!
 
Discrete Optimization Models for Homeland Security and Disaster Management
Discrete Optimization Models for Homeland Security and Disaster ManagementDiscrete Optimization Models for Homeland Security and Disaster Management
Discrete Optimization Models for Homeland Security and Disaster Management
 
Should a football team run or pass? A linear programming approach to game theory
Should a football team run or pass? A linear programming approach to game theoryShould a football team run or pass? A linear programming approach to game theory
Should a football team run or pass? A linear programming approach to game theory
 
Integer programming for locating ambulances
Integer programming for locating ambulancesInteger programming for locating ambulances
Integer programming for locating ambulances
 
Screening Commercial Aviation Passengers in the Aftermath of September 11, 2001
Screening Commercial Aviation Passengers in the Aftermath of September 11, 2001Screening Commercial Aviation Passengers in the Aftermath of September 11, 2001
Screening Commercial Aviation Passengers in the Aftermath of September 11, 2001
 
Women in engineering luncheon presentation at CASE 2013 (IEEE conference on a...
Women in engineering luncheon presentation at CASE 2013 (IEEE conference on a...Women in engineering luncheon presentation at CASE 2013 (IEEE conference on a...
Women in engineering luncheon presentation at CASE 2013 (IEEE conference on a...
 
So you're thinking about graduate school in operations research, math, or eng...
So you're thinking about graduate school in operations research, math, or eng...So you're thinking about graduate school in operations research, math, or eng...
So you're thinking about graduate school in operations research, math, or eng...
 
Technical writing tips
Technical writing tipsTechnical writing tips
Technical writing tips
 

Recently uploaded

SCHIZOPHRENIA Disorder/ Brain Disorder.pdf
SCHIZOPHRENIA Disorder/ Brain Disorder.pdfSCHIZOPHRENIA Disorder/ Brain Disorder.pdf
SCHIZOPHRENIA Disorder/ Brain Disorder.pdfSELF-EXPLANATORY
 
Transport in plants G1.pptx Cambridge IGCSE
Transport in plants G1.pptx Cambridge IGCSETransport in plants G1.pptx Cambridge IGCSE
Transport in plants G1.pptx Cambridge IGCSEjordanparish425
 
National Biodiversity protection initiatives and Convention on Biological Di...
National Biodiversity protection initiatives and  Convention on Biological Di...National Biodiversity protection initiatives and  Convention on Biological Di...
National Biodiversity protection initiatives and Convention on Biological Di...PABOLU TEJASREE
 
The ASGCT Annual Meeting was packed with exciting progress in the field advan...
The ASGCT Annual Meeting was packed with exciting progress in the field advan...The ASGCT Annual Meeting was packed with exciting progress in the field advan...
The ASGCT Annual Meeting was packed with exciting progress in the field advan...Health Advances
 
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
 
Cancer cell metabolism: special Reference to Lactate Pathway
Cancer cell metabolism: special Reference to Lactate PathwayCancer cell metabolism: special Reference to Lactate Pathway
Cancer cell metabolism: special Reference to Lactate PathwayAADYARAJPANDEY1
 
Mammalian Pineal Body Structure and Also Functions
Mammalian Pineal Body Structure and Also FunctionsMammalian Pineal Body Structure and Also Functions
Mammalian Pineal Body Structure and Also FunctionsYOGESH DOGRA
 
Circulatory system_ Laplace law. Ohms law.reynaults law,baro-chemo-receptors-...
Circulatory system_ Laplace law. Ohms law.reynaults law,baro-chemo-receptors-...Circulatory system_ Laplace law. Ohms law.reynaults law,baro-chemo-receptors-...
Circulatory system_ Laplace law. Ohms law.reynaults law,baro-chemo-receptors-...muralinath2
 
RNA INTERFERENCE: UNRAVELING GENETIC SILENCING
RNA INTERFERENCE: UNRAVELING GENETIC SILENCINGRNA INTERFERENCE: UNRAVELING GENETIC SILENCING
RNA INTERFERENCE: UNRAVELING GENETIC SILENCINGAADYARAJPANDEY1
 
Hemoglobin metabolism_pathophysiology.pptx
Hemoglobin metabolism_pathophysiology.pptxHemoglobin metabolism_pathophysiology.pptx
Hemoglobin metabolism_pathophysiology.pptxmuralinath2
 
Gliese 12 b, a temperate Earth-sized planet at 12 parsecs discovered with TES...
Gliese 12 b, a temperate Earth-sized planet at 12 parsecs discovered with TES...Gliese 12 b, a temperate Earth-sized planet at 12 parsecs discovered with TES...
Gliese 12 b, a temperate Earth-sized planet at 12 parsecs discovered with TES...Sérgio Sacani
 
insect taxonomy importance systematics and classification
insect taxonomy importance systematics and classificationinsect taxonomy importance systematics and classification
insect taxonomy importance systematics and classificationanitaento25
 
Richard's entangled aventures in wonderland
Richard's entangled aventures in wonderlandRichard's entangled aventures in wonderland
Richard's entangled aventures in wonderlandRichard Gill
 
Extensive Pollution of Uranus and Neptune’s Atmospheres by Upsweep of Icy Mat...
Extensive Pollution of Uranus and Neptune’s Atmospheres by Upsweep of Icy Mat...Extensive Pollution of Uranus and Neptune’s Atmospheres by Upsweep of Icy Mat...
Extensive Pollution of Uranus and Neptune’s Atmospheres by Upsweep of Icy Mat...Sérgio Sacani
 
mixotrophy in cyanobacteria: a dual nutritional strategy
mixotrophy in cyanobacteria: a dual nutritional strategymixotrophy in cyanobacteria: a dual nutritional strategy
mixotrophy in cyanobacteria: a dual nutritional strategyMansiBishnoi1
 
The importance of continents, oceans and plate tectonics for the evolution of...
The importance of continents, oceans and plate tectonics for the evolution of...The importance of continents, oceans and plate tectonics for the evolution of...
The importance of continents, oceans and plate tectonics for the evolution of...Sérgio Sacani
 
GBSN - Microbiology (Lab 2) Compound Microscope
GBSN - Microbiology (Lab 2) Compound MicroscopeGBSN - Microbiology (Lab 2) Compound Microscope
GBSN - Microbiology (Lab 2) Compound MicroscopeAreesha Ahmad
 
Climate extremes likely to drive land mammal extinction during next supercont...
Climate extremes likely to drive land mammal extinction during next supercont...Climate extremes likely to drive land mammal extinction during next supercont...
Climate extremes likely to drive land mammal extinction during next supercont...Sérgio Sacani
 
INSIGHT Partner Profile: Tampere University
INSIGHT Partner Profile: Tampere UniversityINSIGHT Partner Profile: Tampere University
INSIGHT Partner Profile: Tampere UniversitySteffi Friedrichs
 
Pests of Green Manures_Bionomics_IPM_Dr.UPR.pdf
Pests of Green Manures_Bionomics_IPM_Dr.UPR.pdfPests of Green Manures_Bionomics_IPM_Dr.UPR.pdf
Pests of Green Manures_Bionomics_IPM_Dr.UPR.pdfPirithiRaju
 

Recently uploaded (20)

SCHIZOPHRENIA Disorder/ Brain Disorder.pdf
SCHIZOPHRENIA Disorder/ Brain Disorder.pdfSCHIZOPHRENIA Disorder/ Brain Disorder.pdf
SCHIZOPHRENIA Disorder/ Brain Disorder.pdf
 
Transport in plants G1.pptx Cambridge IGCSE
Transport in plants G1.pptx Cambridge IGCSETransport in plants G1.pptx Cambridge IGCSE
Transport in plants G1.pptx Cambridge IGCSE
 
National Biodiversity protection initiatives and Convention on Biological Di...
National Biodiversity protection initiatives and  Convention on Biological Di...National Biodiversity protection initiatives and  Convention on Biological Di...
National Biodiversity protection initiatives and Convention on Biological Di...
 
The ASGCT Annual Meeting was packed with exciting progress in the field advan...
The ASGCT Annual Meeting was packed with exciting progress in the field advan...The ASGCT Annual Meeting was packed with exciting progress in the field advan...
The ASGCT Annual Meeting was packed with exciting progress in the field advan...
 
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.
 
Cancer cell metabolism: special Reference to Lactate Pathway
Cancer cell metabolism: special Reference to Lactate PathwayCancer cell metabolism: special Reference to Lactate Pathway
Cancer cell metabolism: special Reference to Lactate Pathway
 
Mammalian Pineal Body Structure and Also Functions
Mammalian Pineal Body Structure and Also FunctionsMammalian Pineal Body Structure and Also Functions
Mammalian Pineal Body Structure and Also Functions
 
Circulatory system_ Laplace law. Ohms law.reynaults law,baro-chemo-receptors-...
Circulatory system_ Laplace law. Ohms law.reynaults law,baro-chemo-receptors-...Circulatory system_ Laplace law. Ohms law.reynaults law,baro-chemo-receptors-...
Circulatory system_ Laplace law. Ohms law.reynaults law,baro-chemo-receptors-...
 
RNA INTERFERENCE: UNRAVELING GENETIC SILENCING
RNA INTERFERENCE: UNRAVELING GENETIC SILENCINGRNA INTERFERENCE: UNRAVELING GENETIC SILENCING
RNA INTERFERENCE: UNRAVELING GENETIC SILENCING
 
Hemoglobin metabolism_pathophysiology.pptx
Hemoglobin metabolism_pathophysiology.pptxHemoglobin metabolism_pathophysiology.pptx
Hemoglobin metabolism_pathophysiology.pptx
 
Gliese 12 b, a temperate Earth-sized planet at 12 parsecs discovered with TES...
Gliese 12 b, a temperate Earth-sized planet at 12 parsecs discovered with TES...Gliese 12 b, a temperate Earth-sized planet at 12 parsecs discovered with TES...
Gliese 12 b, a temperate Earth-sized planet at 12 parsecs discovered with TES...
 
insect taxonomy importance systematics and classification
insect taxonomy importance systematics and classificationinsect taxonomy importance systematics and classification
insect taxonomy importance systematics and classification
 
Richard's entangled aventures in wonderland
Richard's entangled aventures in wonderlandRichard's entangled aventures in wonderland
Richard's entangled aventures in wonderland
 
Extensive Pollution of Uranus and Neptune’s Atmospheres by Upsweep of Icy Mat...
Extensive Pollution of Uranus and Neptune’s Atmospheres by Upsweep of Icy Mat...Extensive Pollution of Uranus and Neptune’s Atmospheres by Upsweep of Icy Mat...
Extensive Pollution of Uranus and Neptune’s Atmospheres by Upsweep of Icy Mat...
 
mixotrophy in cyanobacteria: a dual nutritional strategy
mixotrophy in cyanobacteria: a dual nutritional strategymixotrophy in cyanobacteria: a dual nutritional strategy
mixotrophy in cyanobacteria: a dual nutritional strategy
 
The importance of continents, oceans and plate tectonics for the evolution of...
The importance of continents, oceans and plate tectonics for the evolution of...The importance of continents, oceans and plate tectonics for the evolution of...
The importance of continents, oceans and plate tectonics for the evolution of...
 
GBSN - Microbiology (Lab 2) Compound Microscope
GBSN - Microbiology (Lab 2) Compound MicroscopeGBSN - Microbiology (Lab 2) Compound Microscope
GBSN - Microbiology (Lab 2) Compound Microscope
 
Climate extremes likely to drive land mammal extinction during next supercont...
Climate extremes likely to drive land mammal extinction during next supercont...Climate extremes likely to drive land mammal extinction during next supercont...
Climate extremes likely to drive land mammal extinction during next supercont...
 
INSIGHT Partner Profile: Tampere University
INSIGHT Partner Profile: Tampere UniversityINSIGHT Partner Profile: Tampere University
INSIGHT Partner Profile: Tampere University
 
Pests of Green Manures_Bionomics_IPM_Dr.UPR.pdf
Pests of Green Manures_Bionomics_IPM_Dr.UPR.pdfPests of Green Manures_Bionomics_IPM_Dr.UPR.pdf
Pests of Green Manures_Bionomics_IPM_Dr.UPR.pdf
 

Delivering emergency medical services:Research, theory, and application

  • 1. Delivering emergency medical services: Research, theory, and application Laura Albert Industrial & Systems Engineering University of Wisconsin-Madison laura@engr.wisc.edu punkrockOR.com @lauraalbertphd 1 This work was in part supported by the U.S. Department of the Army under Grant Award Number W911NF-10-1-0176 and by the National Science Foundation under Award No. 1054148, 1444219, 1541165.
  • 2. The road map • How do emergency medical service (EMS) systems work? • How do we know when EMS systems work well? • How can we improve how well EMS systems work? • Where is EMS search in operations research going? • Where do they need to go? 2
  • 3. Collaborators Maria Mayorga North Carolina State University Students Sardar Ansari Ben Grannan Soovin Yoon 3
  • 4. One sentiment in the 1960s in the US “If we can land a man on the moon…” ...why can't we attack fundamental societal problems using math and operations research? 4
  • 5. OR in EMS, fire & policing 5 The President’s Commission on Law Enforcement and the Administration of Justice (1965) Al Blumstein chaired the Commission’s Science and Technology Task Force (CMU) Richard Larson did much of the early work (MIT) 1972 1972
  • 6. A golden age of public safety research began in the 1960s • New York City / RAND Institute Collaboration • Between 1963 – 1968, fire alarms in NYC increased 96% while operating expenses remained the same • New York City used simulation for the first time! • The research was put into practice • Public safety research applications were influential and productive in the field of operations research • Queueing, integer programming, simulation, data analytics • Many applied operations research papers appeared in the best journals • The research won major awards (Lanchester, Edelman, NATO Systems Science Prize) 6
  • 7. Early urban operations research models 7 Set cover / maximum cover models How can we “cover” the maximum number of locations with ambulances? Church, R., & ReVelle, C. (1974). The maximal covering location problem. Papers in regional science, 32(1), 101-118. Markov models How many fire engines should we send? Swersey, A. J. (1982). A Markovian decision model for deciding how many fire companies to dispatch. Management Science, 28(4), 352- 365. Analytics How far will a fire engine travel to a call? Kolesar, P., & Blum, E. H. (1973). Square root laws for fire engine response distances. Management Science, 19(12), 1368-1378. Hypercube queueing models What is the probability that our first choice ambulance is unavailable for this call? Larson, R. C. (1974). A hypercube queuing model for facility location and redistricting in urban emergency services. Computers & Operations Research, 1(1), 67-95.
  • 8. Anatomy of a 911 call Response time Service provider: Emergency 911 call Unit dispatched Unit is en route Unit arrives at scene Service/care provided Unit leaves scene Unit arrives at hospital Patient transferred Unit returns to service 8 Response time from the patient’s point of view
  • 9. EMS design varies by community: One size does not fit all 9McLay, L.A., 2011. Emergency Medical Service Systems that Improve Patient Survivability. Encyclopedia of Operations Research in the area of “Applications with Societal Impact,” John Wiley & Sons, Inc., Hoboken, NJ (published online: DOI: 10.1002/9780470400531.eorms0296) Fire and EMS vs. EMS Paid staff vs. volunteers Publicly run vs. privately run Emergency medical technician (EMT) vs. Paramedic (EMTp) Mix of vehicles Ambulance location, relocation, and relocation on-the-fly Mutual aid
  • 10. Performance standards come from the National Fire Protection Agency (NFPA) • NFPA 1710 guidelines for departments with paid staff • 5 minute response time for first responding vehicle • 9 minute response time for first advanced life support vehicle • Must achieve these goals 90% of the time for all calls • Similar guidelines for volunteer agencies in NFPA 1720 allow for 9-14 minute response times • Guidelines based on medical research for cardiac arrest patients and time for structural fires to spread • Short response times only critical for some patient types: cardiac arrest, shock, myocardial infarction • Most calls are lower-acuity • Many communities use different response time goals 10
  • 11. Operationalizing recommendations when sending ambulances to calls Priority dispatch: … but which ambulance when there is a choice? 11 Type Capability Response Time Priority 1 Advanced Life Support (ALS) Emergency Send ALS and a fire engine/BLS E.g., 9 minutes (first unit) Priority 2 Basic Life Support (BLS) Emergency Send BLS and a fire engine if available E.g., 13 minutes Priority 3 Not an emergency Send BLS E.g., 16 minutes
  • 12. Performance standards National Fire Protection Agency (NFPA) standard yields a coverage objective function for response times Most common response time threshold (RTT): 9 minutes for 80% of calls • Easy to measure • Intuitive • Unambiguous 12
  • 13. Response times vs. cardiac arrest survival 13 CDF of calls for service covered Response time (minutes) 9 80%
  • 14. What is the best response time threshold? • Guidelines suggest 9 minutes • Medical research suggests ~5 minutes • But this would disincentive 5-9 minute responses 14 Responses no longer “count”
  • 15. What is the best response time threshold? • Guidelines suggest 9 minutes • Medical research suggests ~5 minutes • But this would disincentive 5-9 minute responses • Which RTT is best for design of the system? 15
  • 16. What is the best response time threshold based on retrospective survival rates? Decision context is locating and dispatching ALS ambulances • Discrete optimization model to locate ambulances * • Markov decision process model to dispatch ambulances 16 * McLay, L.A. and M.E. Mayorga, 2010. Evaluating Emergency Medical Service Performance Measures. Health Care Management Science 13(2), 124 - 136
  • 17. Survival and dispatch decisions 17 Across different ambulance configurations Across different call volumes McLay, L.A., Mayorga, M.E., 2011. Evaluating the Impact of Performance Goals on Dispatching Decisions in Emergency Medical Service. IIE Transactions on Healthcare Service Engineering 1, 185 – 196 Minimize un-survivability when altering dispatch decisions
  • 18. Ambulance Locations, N=7 Best for patient survival / 8 Minute RTT = one ambulance = two ambulances McLay, L.A. and M.E. Mayorga, 2010. Evaluating Emergency Medical Service Performance Measures. Health Care Management Science 13(2), 124 - 136 Suburban area –> (vs. rural areas) <– Interstates 18
  • 19. Ambulance Locations, N=7 10 Minute RTT = one ambulance = two ambulances McLay, L.A. and M.E. Mayorga, 2010. Evaluating Emergency Medical Service Performance Measures. Health Care Management Science 13(2), 124 - 136 19
  • 20. Ambulance Locations, N=7 5 Minute RTT = one ambulance = two ambulances McLay, L.A. and M.E. Mayorga, 2010. Evaluating Emergency Medical Service Performance Measures. Health Care Management Science 13(2), 124 - 136 20
  • 22. Optimal dispatching policies using Markov decision process models 911 call Unit dispatched Unit is en route Unit arrives at scene Service/care provided Unit leaves scene Unit arrives at hospital Patient transferred Unit returns to service Determine which ambulance to send based on classified priority Classified priority (H or L) True priority HT or LT 22 Information changes over the course of a call Decisions made based on classified priority. Performance metrics based on true priority. Classified customer risk Map Priority 1, 2, 3 call types to high-priority (𝐻𝐻) or low-priority (𝐿𝐿) Calls of the same type treated the same True customer risk Map all call types to high-priority (𝐻𝐻𝑇𝑇) or low-priority (𝐿𝐿𝑇𝑇)
  • 23. Optimal dispatching policies using Markov decision process models Optimality equations: 𝑉𝑉𝑘𝑘 𝑆𝑆𝑘𝑘 = max 𝑥𝑥𝑘𝑘∈𝑋𝑋(𝑆𝑆𝑘𝑘) 𝐸𝐸 𝑢𝑢𝑖𝑖𝑖𝑖 𝜔𝜔 𝑥𝑥𝑘𝑘 + 𝑉𝑉𝑘𝑘+1 𝑆𝑆𝑘𝑘+1 𝑆𝑆𝑘𝑘, 𝑥𝑥𝑘𝑘, 𝜔𝜔 Formulate problem as an undiscounted, infinite-horizon, average reward Markov decision process (MDP) model • The state 𝒔𝒔𝒌𝒌 ∈ 𝑆𝑆 describes the combinations of busy and free ambulances. • 𝑋𝑋(𝒔𝒔𝑘𝑘) denotes the set of actions (ambulances to dispatch) available in state 𝒔𝒔𝒌𝒌. • Reward 𝑢𝑢𝑖𝑖𝑖𝑖 𝜔𝜔 depend on true priority (random). • Transition probabilities: the state changes when (1) one of the busy servers completes service or (2) a server is assigned to a new call. Select best ambulance to send Value in current state Values in (possible) next states (Random) reward based on true patient priority
  • 24. Under- or over-prioritize • Assumption: No priority 3 calls are truly high-priority Case 1: Under-prioritize with different classification accuracy Case 2: Over-prioritize Pr1 Pr2 Pr3 Pr1 Pr2 Pr3 HT HT Pr1 Pr2 Pr3 HT Pr1 Pr2 Pr3 HT Informational accuracy captured by: 𝛼𝛼 = 𝑃𝑃 𝐻𝐻𝑇𝑇 𝐻𝐻 𝑃𝑃(𝐻𝐻𝑇𝑇|𝐿𝐿) 24 Classified high-priority Classified low-priority Improved accuracy
  • 25. Structural properties RESULT It is more beneficial for an ambulance to be idle than busy. RESULT It is more beneficial for an ambulance to be serving closer patients. RESULT It is not always optimal to send the closest ambulance, even for high priority calls.
  • 26. Coverage 0 10 20 30 40 50 0.405 0.41 0.415 0.42 0.425 0.43 0.435 0.44 0.445 α Expectedcoverage Optimal Policy, Case 1 Optimal Policy, Case 2 Closest Ambulance 26 Better accuracy
  • 27. Low and high priority calls Conditional probability that the closest unit is dispatched given initial classification High-priority calls Low-priority calls0 10 20 30 40 50 0.98 0.985 0.99 0.995 1 1.005 α Proportionclosestambulanceisdispatched Closest Ambulance Optimal Policy, Case 1 Optimal Policy, Case 2 0 10 20 30 40 50 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 α Proportionclosestambulanceisdispatched Closest Ambulance Optimal Policy, Case 1 Optimal Policy, Case 2 Classified high-priority Classified low-priority 27
  • 28. Case 1 (𝛼𝛼 = ∞), Case 2 policies High-priority calls Case 2: First to send to high-priority calls Station 1 2 3 4 Case 2: Second to send to high-priority calls Station 1 2 3 4 Service can be improved via optimization of backup service and response to low-priority patients Rationed for high-priority calls Rationed for low- priority calls 28
  • 30. Ambulance response districts How should we locate ambulances? How should we design response districts around each ambulance? • Multiple ambulances per station • Ambulance unavailability (spatial queueing) • Uncertain travel times / Fractional coverage • Workload balancing: all ambulances do the same amount of work 30Ansari, S., McLay, L.A., Mayorga, M.E., 2016. A maximum expected covering problem for locating and dispatching servers. Transportation Science, published online in Articles in Advance. Spatial queueing model Mixed integer programming model
  • 31. Districting model Mixed Integer Linear Program max ∑𝑤𝑤∈𝑊𝑊 ∑𝑗𝑗∈𝐽𝐽 ∑𝑝𝑝=1 𝑠𝑠 ∑ 𝑚𝑚=1 min(𝑐𝑐 𝑤𝑤,𝑠𝑠−𝑝𝑝+1) 𝑞𝑞𝑗𝑗𝑗𝑗𝑗𝑗 1 − 𝑟𝑟 𝑚𝑚 𝑟𝑟 𝑝𝑝−1 𝜆𝜆𝑗𝑗 𝐻𝐻 𝑅𝑅𝑤𝑤𝑤𝑤 𝑧𝑧𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤 subject to ∑𝑝𝑝=1 𝑠𝑠 ∑ 𝑚𝑚=1 𝜅𝜅 𝑤𝑤𝑤𝑤 𝑧𝑧𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤 ≤ 1, 𝑗𝑗 ∈ 𝐽𝐽, 𝑤𝑤 ∈ 𝑊𝑊 ∑𝑝𝑝=1 𝑠𝑠 ∑ 𝑚𝑚=1 𝜅𝜅 𝑤𝑤𝑤𝑤 𝑧𝑧𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤 ≤ 𝑦𝑦𝑤𝑤, 𝑗𝑗 ∈ 𝐽𝐽, 𝑤𝑤 ∈ 𝑊𝑊 ∑𝑤𝑤∈𝑊𝑊 𝑥𝑥𝑤𝑤𝑤𝑤𝑤𝑤 = 1, 𝑗𝑗 ∈ 𝐽𝐽, 𝑝𝑝 = 1, … , 𝑠𝑠 ∑𝑝𝑝=1 𝑠𝑠 𝑥𝑥𝑤𝑤𝑤𝑤𝑤𝑤 = 𝑦𝑦𝑤𝑤 , 𝑗𝑗 ∈ 𝐽𝐽, 𝑤𝑤 ∈ 𝑊𝑊 𝑥𝑥𝑤𝑤𝑤𝑤𝑤𝑤𝑤 = ∑𝑝𝑝=max 1,𝑝𝑝′−𝑐𝑐 𝑤𝑤+1 𝑝𝑝𝑝 ∑ 𝑚𝑚=𝑝𝑝′−𝑝𝑝+1 𝜅𝜅 𝑤𝑤𝑤𝑤 𝑧𝑧𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤 , 𝑗𝑗 ∈ 𝐽𝐽, 𝑤𝑤 ∈ 𝑊𝑊, 𝑝𝑝′ = 1, … , 𝑠𝑠 ∑𝑤𝑤∈𝑊𝑊 𝑦𝑦𝑤𝑤 = 𝑠𝑠 𝑦𝑦𝑤𝑤 ≤ 𝑐𝑐𝑤𝑤, 𝑤𝑤 ∈ 𝑊𝑊 𝑟𝑟 − 𝛿𝛿 𝑦𝑦𝑤𝑤 ≤ ∑𝑗𝑗∈𝐽𝐽 ∑𝑝𝑝=1 𝑠𝑠 ∑ 𝑚𝑚=1 𝜅𝜅 𝑤𝑤𝑤𝑤 𝜆𝜆𝑗𝑗 𝐻𝐻 + 𝜆𝜆𝑗𝑗 𝐿𝐿 𝑞𝑞𝑗𝑗𝑗𝑗𝑗𝑗 1 − 𝑟𝑟 𝑚𝑚 𝑟𝑟 𝑝𝑝−1 𝜏𝜏𝑤𝑤𝑤𝑤 𝑧𝑧𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤 ≤ 𝑟𝑟 + 𝛿𝛿 𝑦𝑦𝑤𝑤, 𝑤𝑤 ∈ 𝑊𝑊 𝑥𝑥𝑤𝑤𝑤𝑤𝑤𝑤 ≥ 𝑥𝑥𝑤𝑤𝑤𝑤𝑤, 𝑗𝑗 ∈ 𝐽𝐽, 𝑤𝑤 ∈ 𝑊𝑊, 𝑗𝑗′ ∈ 𝑁𝑁𝑤𝑤𝑤𝑤 𝑦𝑦𝑤𝑤 ∈ 𝑍𝑍0 + , 𝑤𝑤 ∈ 𝑊𝑊 𝑥𝑥𝑤𝑤𝑤𝑤𝑤𝑤 ∈ 0,1 , 𝑤𝑤 ∈ 𝑊𝑊, 𝑗𝑗 ∈ 𝐽𝐽, 𝑝𝑝 = 1, … , 𝑠𝑠 𝑧𝑧𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤 ∈ 0,1 , 𝑤𝑤 ∈ 𝑊𝑊, 𝑗𝑗 ∈ 𝐽𝐽, 𝑝𝑝 = 1, … , 𝑠𝑠, 𝑚𝑚 = 1, … , 𝑐𝑐𝑤𝑤 31 Every customer has all the priorities and the number of assignments to a station is equal to the number of servers located at that station A customer location is not assigned to a station more than once and no call location is assigned to a closed station Linking constraints Balance the load amongst the servers Locate 𝑠𝑠 servers with no more than 𝑐𝑐𝑤𝑤 per station Expected coverage Contiguous first priority districts Binary and integrality constraints on the variables
  • 32. Parameters • 𝐽𝐽: set of all customer (demand) nodes • 𝑊𝑊: set of all potential station locations • 𝑠𝑠: total number of servers in the system • 𝜆𝜆𝑗𝑗 𝐻𝐻 (𝜆𝜆𝑗𝑗 𝐿𝐿 ): mean high-priority (low-priority) call arrival rates from node 𝑗𝑗 • 𝜆𝜆: system-wide total call arrival rate • 𝜏𝜏𝑤𝑤𝑤𝑤: mean service time for calls originated from node 𝑗𝑗 and served by a server from a potential station 𝑤𝑤. • 𝜏𝜏: system-wide mean service time • 𝑐𝑐𝑤𝑤: capacity of station 𝑤𝑤 32 • 𝑟𝑟: system-wide average server utilization • 𝑃𝑃𝑠𝑠: loss probability (probability that all 𝑠𝑠 servers are busy) • 𝑅𝑅𝑤𝑤𝑤𝑤: expected proportion of calls from 𝑗𝑗 that are reached by servers from station 𝑤𝑤 in nine minutes • 𝑞𝑞𝑗𝑗𝑗𝑗𝑗𝑗: correction factor for customer 𝑗𝑗's 𝑝𝑝th priority server at which there are 𝑚𝑚 servers located. • 𝑁𝑁𝑤𝑤𝑤𝑤: set of demand nodes that are neighbors to 𝑗𝑗 and are closer to station 𝑤𝑤 than 𝑗𝑗. Decision variables • 𝑦𝑦𝑤𝑤 = number of servers located at station 𝑤𝑤, 𝑤𝑤 ∈ 𝑊𝑊. • 𝑧𝑧𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤= 1 if there are 𝑝𝑝 − 1 servers located at stations that node 𝑗𝑗 prefers over 𝑤𝑤 and there are 𝑚𝑚 servers located at station 𝑤𝑤, 𝑤𝑤 ∈ 𝑊𝑊, 𝑗𝑗 ∈ 𝐽𝐽, 𝑝𝑝 = 1, … , 𝑠𝑠, 𝑚𝑚 = 1, … , 𝑐𝑐𝑤𝑤 and 0 otherwise. • 𝑥𝑥𝑤𝑤𝑤𝑤𝑤𝑤= 1 if 𝑝𝑝′ < 𝑝𝑝 < 𝑠𝑠 − 𝑝𝑝𝑝𝑝 where are 𝑝𝑝′ is the number of servers located at stations that node 𝑗𝑗 prefers over 𝑤𝑤, and 𝑝𝑝′′ is the number of servers located at stations that node 𝑗𝑗 prefers less than 𝑤𝑤, 𝑤𝑤 ∈ 𝑊𝑊, 𝑗𝑗 ∈ 𝐽𝐽, 𝑝𝑝 = 1, … , 𝑠𝑠, and 0 otherwise.
  • 33. Results RESULT The Base model that does not maintain contiguity or a balanced load amongst the ambulances is NP-complete. • reduction from k-median RESULT The first priority response districts for the Base model are contiguous if there is no more than one ambulance per station. RESULT Identifying districts that balance the workload is NP-complete. • reduction from bin packing RESULT Reduced model to assign only the top 𝑠𝑠′ ≤ 𝑠𝑠 ambulances • Not trivial, allows model to scale up to have many ambulances 33
  • 35. First priority districts for the base model • Base Model: no workload balancing or contiguity constraints
  • 36. Model with workload balancing but no contiguity constraints • First Priority Districts for one time period
  • 37. First priority districts may be different if we balance the workload • Workload balancing • Contiguous first priority districts Two ambulances
  • 38. Coordinating multiple types of vehicles is not intuitive due to double response • Not intuitive how to use multiple types of vehicles • ALS ambulances / BLS ambulances (2 EMTp/EMT) • ALS quick response vehicles (QRVs) (1 EMTp) • Double response = both ALS and BLS units dispatched • Downgrades / upgrades for Priority 1 / 2 calls • Who transports the patient to the hospital? • Research goal: operationalize guidelines for sending vehicle types to prioritized patients • (Linear) integer programming model for a two vehicle-type system: ALS Non-transport QRVs and BLS ambulances 38
  • 39. The more ALS QRVs in use, the better the coverage 39
  • 40. Application in a real setting: the results were better than anticipated 40 Achievement Award Winner for Next-Generation Emergency Medical Response Through Data Analysis & Planning (Best in Category winner), National Association of Counties, 2010. McLay, L.A., Moore, H. 2012. Hanover County Improves Its Response to Emergency Medical 911 Calls. Interfaces 42(4), 380-394.
  • 41. Where do EMS systems need to go? 41
  • 42. EMS = Prehospital care Operations Research • Efficiency • Optimality • Utilization • System-wide performance Healthcare • Efficacy • Access • Resources/costs • “Patient centered outcomes” 42 Healthcare Transportation Public sector Common ground?
  • 43. More thoughts on patient centered outcomes Operational measures used to evaluate emergency departments • Length of stay • Throughput Increasing push for more health metrics • Disease progression • Recidivism Many challenges for EMS modeling • Health metrics needed • Information collected at scene • Equity models a good vehicle for examining health measures (access, cost, efficacy) 43 Healthcare Transportation Public sector
  • 45. EMS response during/after extreme events depends on critical infrastructure 45 EMS service largely dependent on other interdependent systems and networks Decisions may be very different during disasters • Ask patients to wait for service • Patient priorities may be dynamic • Evacuate patients from hospitals • Massive coordination with other agencies (mutual aid) Two main research streams exist: 1. Normal operations 2. Disaster operations More guidance needed for “typical” emergencies and mass casualty events E.g., Health risks during/after hurricanes: • Increased mortality, traumatic injuries, low-priority calls • Carbon monoxide poisoning, Electronic health devices * Caused by power failures
  • 46. Thank you! 46 1. McLay, L.A., Mayorga, M.E., 2013. A model for optimally dispatching ambulances to emergency calls with classification errors in patient priorities. IIE Transactions 45(1), 1—24. 2. McLay, L.A., Mayorga, M.E., 2011. Evaluating the Impact of Performance Goals on Dispatching Decisions in Emergency Medical Service. IIE Transactions on Healthcare Service Engineering 1, 185 – 196 3. McLay, L.A., Mayorga, M.E., 2014. A dispatching model for server-to-customer systems that balances efficiency and equity. To appear in Manufacturing & Service Operations Management, doi:10.1287/msom.1120.0411 4. Ansari, S., McLay, L.A., Mayorga, M.E., 2015. A maximum expected covering problem for locating and dispatching servers. To appear in Transportation Science. 5. Kunkel, A., McLay, L.A. 2013. Determining minimum staffing levels during snowstorms using an integrated simulation, regression, and reliability model. Health Care Management Science 16(1), 14 – 26. 6. McLay, L.A., Moore, H. 2012. Hanover County Improves Its Response to Emergency Medical 911 Calls. Interfaces 42(4), 380-394. 7. Leclerc, P.D., L.A. McLay, M.E. Mayorga, 2011. Modeling equity for allocating public resources. Community-Based Operations Research: Decision Modeling for Local Impact and Diverse Populations, Springer, p. 97 – 118. 8. McLay, L.A., Brooks, J.P., Boone, E.L., 2012. Analyzing the Volume and Nature of Emergency Medical Calls during Severe Weather Events using Regression Methodologies. Socio-Economic Planning Sciences 46, 55 – 66. 9. McLay, L.A., 2011. Emergency Medical Service Systems that Improve Patient Survivability. Encyclopedia of Operations Research in the area of “Applications with Societal Impact,” John Wiley & Sons, Inc., Hoboken, NJ (published online: DOI: 10.1002/9780470400531.eorms0296) 10. McLay, L.A. and M.E. Mayorga, 2010. Evaluating Emergency Medical Service Performance Measures. Health Care Management Science 13(2), 124 - 136 laura@engr.wisc.edu punkrockOR.com @lauraalbertphd