This document discusses different methods for analyzing construction delays. It begins with an overview of forensic schedule analysis and definitions. It then examines the main delay analysis methodologies: as-planned vs as-built, impacted as-planned, time impact analysis, and as-built but for. For each methodology, it outlines the approach, strengths, and weaknesses. It emphasizes that the most suitable methodology depends on the specific project factors and available information. It recommends following industry guidance and notes that facts should take precedence over theoretical analyses. The document aims to provide an unbiased overview of delay analysis options to help practitioners choose the right approach.

1. Methods of Delay Analysis
Requirements and Developments
Katrin Enders
Hill International, London UK
Frankfurt, 29 September 2015

2. OVERVIEW
Overview – Definition Forensic Schedule Analysis
Approach – Delay Analysis Methodologies pro & cons
Findings – Choosing a methodology, Fact is King, Guidance
Conclusions
2

3. “‘Beware the dark arts’ was the sage advice of Albus
Dumbledore to the young Harry Potter. Besides budding wizards,
construction clients (at the project or dispute resolution stages),
contractors and lawyers would be equally well served by this
advice when it comes to the difficult subject of delay
analysis"...“delay analysis like Lord Voldamort, comes in many
guises and it seems there is a spell for every circumstance. ‘What
would you like conjured … err … proven, sir? Let me just mix up
some ‘fragnets’, ‘lags’, eye of newt and … hey presto!’”
OVERVIEW – DEFINITION
3
(cited: BEWARE THE DARK ARTS! DELAY ANALYSIS AND THE PROBLEMS WITH RELIANCE ON TECHNOLOGY, David Barry, 2009 )

4. • FORENSIC SCHEDULE ANALYSIS
• “… refers to the study and investigation of events using CPM or other
recognized schedule calculation methods for potential use in a legal
proceeding.”
• “… the study of how actual events interacted in the context of a
complex model for the purpose of understanding the significance of a
specific deviation or series of deviations from some baseline model and
their role in determining the sequence of tasks within the complex
network.”
(cited: AACE® International Recommended Practice No. 29R‐03 FORENSIC SCHEDULE ANALYSIS TCM Framework)
OVERVIEW – DEFINITION
4

5. APPROACH
Overview – Definition Forensic Schedule Analysis and Nomenclature
Approach – Delay Analysis Methodologies pro & cons
Findings – Choosing a methodology, Fact is King, Guidance
Conclusions
5

6. APPROACH – DELAY ANALYSIS METHODOLOGIES
6
TWO
Types
FOUR
Categories*
TWO
Types
FOUR
Categories*
* See for example the Society of Construction Law “Protocol on Delay and Disruption”, or Association for the Advancement of Cost Engineering Recommended Practice No.29R-03
“Forensic Schedule Analysis”
• As‐planned versus As‐built
• As‐Built But For
LOOKING BACKLOOKING BACK
Retrospective Analyses
LOOKING FORWARDLOOKING FORWARD
Prospective Analyses
• Time‐Impact Analysis
• Impacted As‐planned

7. • is the most basic method of analysis
• is observational – no changes are made to the programme
• straightforward comparison between the planned vs the actual
performance of the work
• can only be carried out retrospectively (requires as‐built programme/or at
least the overall as‐built completion date)
7
Strengths Weakness
• is very simple and therefore
easy to understand
• can be performed with
rudimentary base data (e.g.
when detail and logic of the as‐
planned programme is unavailable,
and no detailed progress records
other than the overall as‐built
programme are available)
• Static critical path
• fails to fulfil the fundamental
requirement to demonstrate the
causal link between a delay event and
its alleged effect
• does not deal adequately with
concurrent delay
APPROACH – AS‐PLANNED VS AS‐BUILT (APAB)

8. Claim
Planned CP
TimescaleActivities
As‐built CP
Compare As‐Planned vs As‐Built
(delays)
Contractual
Completion
Date
Actual
Completion
Date
(delays and disruptions)
APPROACH – AS‐PLANNED VS AS‐BUILT (APAB)

9. APPROACH – IMPACTED AS‐PLANNED (IAP)
9
• is a prospective methodology
• delay effect is measured by imposing events on a model of the original
programme (Baseline)
• does not rely on any actual progress that has been made
• requires a robust and reliable original programme that reflects the
indented sequence and the Scope of Work
Strengths Weakness
• relatively simple to carry out and
to understand
• No as‐built required (likely choice
when planned programme is available,
no significant changes in the sequence
during the project execution, few
delaying events, and when there is
little or no progress records)
• cannot be used for complex projects
• used to quantify potential delays rather
and actual
• concurrent delays easily overlooked
• assumes that the baseline was
achievable
• does not take actual progress/ resources
into account
• not reliable in dispute resolution

10. Event
Event
TimescaleActivities
Event
Claim
Event
Event
Event
10
APPROACH – IMPACTED AS‐PLANNED (IAP)

11. APPROACH – TIME IMPACT ANALYSIS (TIA)
11
• prospective and dynamic method – but can be applied retrospectively
• takes account of progress and timing of delay events on the Works
• requires reliable as‐built data to update the programme (hence, if detailed and
regular progress data is not available then this method cannot be used)
• a reliable baseline programme is essential (ideally reflects the execution of the
planned project using sound construction logic)
• often undertaken in time slices (windows)
Strengths Weakness
• has a proven track‐record in
forensic application
• preferred method of the SCL
Protocol
• based on a dynamic and changing
critical path
• demonstrates cause and effect
• time consuming (to determine the factual
background and correct logic associated
with progress records and delay events)
• requires considerable degree of
expertise and technical knowledge
• hence, difficult to communicate, highly
complex

12. Activity 1
Activity 2
Activity 3
Project
Completion
Date of
Event
TimescaleActivities
Progress behind
on this activity.
Delay to Project
Completion
Delay to Project
Completion (2)
Delay Event
• Delay (1) caused by poor progress
• Delay (2) caused by event
• Claim = difference between D (1) and D (2)
12
APPROACH – TIME IMPACT ANALYSIS (TIA)

13. APPROACH – AS‐BUILT BUT FOR (ABBF)
13
• retrospective method also known as Collapsed As‐built (CAB)
• relies on a detailed reconstruction of the as‐built programme
• normally restricted to after‐the‐event analyses in forensic work
• does have a limited prospective capability (can be used to demonstrate the effect
of a delay on the completed part of an incomplete project)
• has been proven to be reliable in dispute resolution/ claims
• If done properly can demonstrates effect and cause/ takes account of
concurrence
Strengths Weakness
• greatest strength for forensic work
is that it is fact based (based on as‐
build)
• not reliant upon an as‐planned
programme
• complicated method hence, difficult to
execute and to explain
• difficult to establish a dynamic as‐built
schedule (as complicated to determine and
model logic)
• requires detailed as‐build/ progress
records

14. • Identify Planned Period & As‐built
Planned
period
Planned
Completion
As‐built
Actual
Completion
14
APPROACH – AS‐BUILT BUT FOR (ABBF)

15. • Identify Delays
Planned
period
As‐built
Planned
Completion
Actual
Completion
15
APPROACH – AS‐BUILT BUT FOR (ABBF)

16. • ‘Zero’ delays
Actual
CompletionPlanned
period
Planned
Completion
Actual Completion ‘but for’
delays
As‐built
16
APPROACH – AS‐BUILT BUT FOR (ABBF)

17. • Quantify Claim
Contract
period
As‐built
Contract
Completion
Culpable or non‐
claimable delays
Claim
period
Actual Completion
‘but for’ delays
Actual
Completion
Extended
Completion
17
APPROACH – AS‐BUILT BUT FOR (ABBF)

18. AACEI RP 29R-03: Forensic Schedule Analysis
Table 1 – Nomenclature Correspondence
ADVANTGES & DISADVANTAGES
NOT PREFERENCE … OR PREJUDICE!
APPROACH – NOMENCLATURE
18

19. FINDINGS
Overview – Definition Forensic Schedule Analysis and Nomenclature
Approach – Delay Analysis Methodologies pro & cons
Findings – Choosing a methodology, Fact is King, Guidance
Conclusions
19

20. Which Method is appropriate, correct, sustainable?
• Legal/Contractual
• What does the jurisdiction/ contract require? (e.g. Concurrency? Likely or Actual delay
to completion? Delay Analysis Method Specified?)
• What information is available?
• Planned, progress, as‐built (Does a lack of information preclude the use of any of the
methods?)
• Time and Money
• Do time/cost constraints eliminate certain options? ((During project/After Project,
Record keeping; Staff available (Engineering/Management),Decision making, Budget)
• Other issues:
• Proportionality, Type of project, Which party, at what stage is the dispute?
FINDINGS – CHOOSING A METHODOLOGY
20

21.  Key Facts:
 At least after an event delay becomes a fact and the Other Party/ the Courts are
interested in what actually happened rather than in what could have happened.
 For an event to affect the completion date it must fall on the critical path of the
project.
 must consider all relevant facts and evidence regardless of a positive or negative
impact in relation to the issues in question
 Delay Analysis should be based on a calculated approach it can not be impressionistic
 Effect and Cause not Cause and Effect
 Are there facts/ evidence available and accessible to verify the cause?
FINDINGS – FACT IS KING
21

22. Recommend Guidance:
 AACEI Recommended Practice (http://www.aacei.org/resources/ppg/)
 SCL Protocol (http://www.scl.org.uk/resources)
FINDINGS – GUIDANCE
22

23. CONCLUSIONS
Overview – Definition Forensic Schedule Analysis and Nomenclature
Approach – Delay Analysis Methodologies pro & cons
Findings – Choosing a methodology, Fact is King, Guidance
Conclusions
23

24. CONCLUSIONS
24
 Conclusions:
 Delay Analysis comes in many guises all with their
advantages and disadvantages
 To chose the most suitable method depends on the
surrounding factors
 Facts and common sense are KING

25. QUESTIONS
Katrin Enders
Associate Director
Hill International (UK) Ltd
11 Pilgrim Street,
London EC4V 6RN
Office: +44 (0)207 618 1200/ 1262
Mobile: +44 (0)7850722796
www.hillintl.com
25
QUESTIONS PLEASE ?

26.  4900 Employees worldwide
 100 Offices in 40 countries
 Construction Claims & Consulting Group
 Project Management Group
 NYSE Global Market
 Founded in 1976
 Employers/Contractors
Hill International (D) GmbH
Prinzregentenstraße 20‐22
80538 München
Munich@hillintl.com
Düsseldorf, Germany
Graf‐ Adolf‐ Platz 15
40213 Düsseldorf
Duesseldorf@hillintl.com
Hamburg, Germany
Am Kaiserkai 1
20457 Hamburg
Hill International UK
London, Hill International UK, Ltd.
11 Pilgrim St
London,
EC4V 6RN
UK
Tel: +44 (0)20 7618 1200
(9 UK Locations)
SERVICES

27. SERVICES
• Compliance
• Tools and Templates
• Guidelines
• Procedures & Work Flows
• Structures
• In House Seminars
• Open Seminars
• Industry Events
• Coaching / Mentoring
• Workshops
• Delay & Disruption
Analysis
• Expert Advisory Services
• Expert Witness Services
• Claims Preparation
• Claims Analysis
• Contract Analysis /
Drafting
• Time Risk Management
• Procurement Strategy
• Contract Advisory
• Staff Augmentation
• Contract Workshops
• Project Audits
Dispute
Avoidance
Dispute
Resolution
Claims
Consulting
Seminars /
Coaching /
Mentoring