Table 16 Optimism Bias Upper Bound Guidance for Civil Engineering Projects

Upper Bound Optimism Bias (%)24

Non-Standard Civil Engineering

Standard Civil Engineering

25

66

20

44

Works Duration

Capital Expenditure

Works Duration

Capital Expenditure

Risk Area Contributions to Upper Bound Optimism Bias (%)25

Non-Standard Civil Engineering

Standard Civil Engineering

Procurement

Complexity of Contract Structure

4

Late Contractor Involvement in Design

< 1

3

Poor Contractor Capabilities

2

16

Government Guidelines

Dispute and Claims Occurred

16

21

Information management

Other (specify)

1

2

Project Specific

Design Complexity

5

8

Degree of Innovation

13

9

Environmental Impact

5

46

22

Other (specify)

3

18

Client Specific

Inadequacy of the Business Case

3

35

8

10

Large Number of Stakeholders

Funding Availability

5

6

Project Management Team

2

Poor Project Intelligence

3

9

14

7

Other (specify)

Environment

Public Relations

9

Site Characteristics

5

10

3

Permits / Consents / Approvals

Other (specify)

External Influences

Political

19

Economic

24

3

7

Legislation / Regulations

8

Technology

6

8

Other (specify)

< 1

1




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24 Note that these are only indicative starting values for calculating optimism bias contributions, because a project's optimism bias profile (contributions from project risk areas) will change during its project life-cycle.

25 Contributions from each project risk area are expressed as a % of the recorded optimism bias. Note: The sum of individual percentages contributions in each column may not add up to 100% due to rounding errors.