10 the nature of planning and control_Operations Management

Slack, Chambers and Johnston, Operations Management, 6th Edition,
© Nigel Slack, Stuart Chambers, and Robert Johnston 201010.1
10.1
Chapter 10
The nature of planning and
control
Pearson Education Ltd. Jules Selmes

10.2
• Planning is a formalization of what is intended to
happen at some time in the future.
• A plan does not guarantee that an event will actually
happen, it is a statement of intention.
• Although plans are based on expectations, during their
implementation things do not always happen as
expected.
• Control is the process of coping with any changes that
affect the plan. It may also mean that an ‘intervention’ will
need to be made in the operation to bring it back ‘on track’.
Planning and control

10.3
Planning is deciding
Control is
what activities should take place in the
operation
when they should take place
what resources should be allocated to them
understanding what is actually happening in
the operation
deciding whether there is a significant deviation
from what should be happening
(if there is deviation) changing resources in order
to affect the operation’s activities.
Planning and control (Continued)

10.4
PLANNING
CONTROL
Significance of planning and controlTimehorizon
Hours/daysDays/weeks/monthsMonths/years
Long-term planning and control
Uses aggregated demand forecasts
Determines resources in aggregated form
Objectives set in largely financial terms
Medium-term planning and control
Uses partially disaggregated demand forecasts
Determines resources and contingencies
Objectives set in both financial and operations
terms
Short-term planning and control
Uses totally disaggregated forecasts or
actual demand
Makes interventions to resources to correct
deviations from plans
Ad hoc consideration of operations objectives.

10.5
Volume-Variety Effect on Planning and Control
• An architect’s practice-- high variety and low volume.
[Planning occurs on a relatively short-term basis. Control
decisions will be relatively in detailed level.]
• The electricity utility--- low variety and high volume.
[Major decisions regarding the capacity of power stations
are made many years in advance. Control decisions will
concern aggregated measures of output like the total
kilowatts of electricity generated.]

10.6
Dependent & Independent demand
• Dependent demand is relatively predictable
because it is dependent upon some factors.
• Some operations will supply demand
without having any firm forward visibility
of customer orders. Decision must be made
based on demand forecasts and in the light
of the risks they are prepared to run of being
out of stock. It’s the nature of Independent
Demand.

10.7
Responding to demand
Resource to
order
Make to stock
Make to order
Dependent
demand
Independent
demand
Each product or
service (large)
compared with
total capacity of
the operation
Each product or
service (small)
compared with
total capacity of
the operation

10.8
P : D ratios
D
P
Produce to stock
D
P
Part produce to order
D
P
Resource to order
Customer
orders
Deliver to customer
Allow time
for delivery
Produce product/service
Allow time
for creation
Obtain resources
Allow time for
resourcing
D
P
Produce to order

10.9
Scheduling Loading
Sequencing
Monitoring
and control
When to
do things?
In what
order to do
things?
How much
to do?
Are activities
going to plan?
The activities of planning and control

10.10
Quality
losses Slow
running
equipment
Equipment
‘idling’ ‘Breakdown’
failure
Set-up and
changeovers
Not worked
(unplanned)
Valuable operating
time
Maximum available time
Loading – The reduction of time available for ‘valuable
operating time’
Not worked
(planned)

10.11
Finite and infinite loading of jobs on three work centres A, B and C. Finite loading
limits the loading on each centre to their capacities, even if it means that jobs will be
late. Infinite loading allows the loading on each centre to exceed their capacities to
ensure that jobs will not be late.
1
2
3
4
5
6
0
Work centre Work centre
A B C A B C
Finite loading Infinite loading
Finite and infinite loading

10.12
In Accident and Emergency departments, patients arrive at
random. Medical staff must rapidly devise a schedule.
Patients with serious illness need urgent attention. Less
urgent cases will have to wait. Routine non-urgent cases
will have the lowest priority of all.
The hospital triage system

10.13
Triage in the police

10.14
Process
stage
Week
12
Week
13
Week
14
Week
15
Week
16
Week
17
Week
18
Job A Job B Job C Job D Job E
Job A Job BJob Y Job X
Job A Job BJob Z Job XJob Y
Job A Job BJob X Job C
Gantt chart showing the schedule for jobs at each
process stage
Initial spec
Pre-coding
Coding
Compact. check
Final test
Job A Job BJob W Job C Job D

10.15
JOB
Mon
5
Tue
6
Wed
7
Thur
8
Fri
9
Mon
12
Tue
13
Table
Shelves
Kitchen
units
Bed
Actual progress
Time now
V
V
Gantt chart showing the schedule for individual
jobs over time
Scheduled
activity time

10.16
JOB
Mon
5
Tue
6
Wed
7
Thur
8
Fri
9
Mon
12
Tue
13
Wood
preparation
Assembly
Finishing
Paint
Scheduled
activity time Actual progress
T
B
B T
S K
S S S
K
KTS
B T
Non-productive timeV
V
Time
now
Gantt chart by activity

10.17
Shift allocation for the technical ‘hot line’
(a) on a daily basis (b) on a weekly basis
(a)
Shift pattern (24-hour clock)
Peter
Jo
Walter Jo
Marie Claire Jo
04:00 08:00 12:00 16:00 20:00
Peter X X X X O O X
Marie X X X X X O O
Claire X X X X O O X
Walter O X X X X X O
Jo O X X X X X O
Mon Tue Wed Thu Fri Sat Sun
Number of staff
required
3 5 5 5 3 2 2
(b)
X OFull day Day off
Shift allocation

10.18
Operation or
processInput Output
Compare
/ replan
Intervention
Plans
A simple model of control
Monitor

10.19
Pull and push philosophies of planning and control
Push control
Work
centre
Work
centre
Work
centre
Work
centre
Instruction on
what to make
and where to
send it
DEMAND
FORECAST
OR
CENTRAL OPERATIONS, PLANNING AND CONTROL SYSTEM

10.20
Pull control
Work
centre DEMAND
Pull and push philosophies of planning and control
(Continued)
Work
centre
Work
centre
Work
centre
Request Request Request Request
Delivery Delivery Delivery Delivery

10 the nature of planning and control_Operations Management

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