Use, abuse, and misuse of optimism bias in civil engineering, how to avoid it.

Estimate, Estimation, Civil Engineering, Cost Management, Whole Life Cycle Costing, Optimism Bias

Optimism bias

Optimism bias is the inclination of people to anticipate better compared to average results from their activities. Basically, Optimism bias in construction projects is the inclination, unknowingly or intentionally, to exaggerate anticipated advantages and minimize the degree of intricacy of the project bringing about underestimates of expenses and timetables. Optimism bias can prompt underestimation of the project term, misjudgment of its advantages, and underestimation of its absolute expense

Why Optimism Bias Is Used in Civil Engineering? 

To work in a highly competitive industry, we really want a sound portion of positivism. However, there is a disadvantage to optimism, it makes blind points and blurs the analytical skills of individuals that they escape the realities. At one point, it can cloud our decisive reasoning and permit us to acknowledge ridiculous presumptions and assessments.

Estimate, Estimation, Civil Engineering, Cost Management, Whole Life Cycle Costing, Optimism Bias
Estimate, Estimation, Civil Engineering, Cost Management, Whole Life Cycle Costing, Optimism Bias

One of the significant difficulties for any project is to make a feasible pattern timetable that guarantees the success of the project rather than setting its way for failure. Optimism bias is therefore used in civil engineering projects to prepare the project schedule along with the estimated costs and expected benefits. However, ended up being broadly acknowledged as a significant reason for unreasonable scheduling for projects.

While setting up the project base, a major concern is the value of the project, for instance, estimated costs and expected profits. One significant way of doing this to be certain of the project value is to really construct it, find whether individuals use it, and check whether it has the ideal impact. What’s more, we have the confusion of isolating the impacts of the change from different changes we make simultaneously.

We can isolate the difference between appraisals and actuals into two sections: bias and random changeability. Bias appears when we sum up and measure the float from the real. It is widely known that in Civil Engineering projects prompts evaluations of project terms that are around 20% more limited than real and with cost overwhelms of around half, even after a thorough conducted analysis. 

Estimate, Estimation, Civil Engineering, Cost Management, Whole Life Cycle Costing, Optimism Bias
Estimate, Estimation, Civil Engineering, Cost Management, Whole Life Cycle Costing, Optimism Bias

Strategy for Calculating Optimism Bias for Cost

The following are the primary steps that are to be taken when calculating optimism bias for cost in a civil engineering project. 

  1. Establish the reference class and the kind of project. 
  2. Settle the phase of the project. 
  3. Settle the appropriate upper-headed value for bias given for the project. 
  4. Determine the contributory variables to the upper bound optimism bias for the venture kind. 
  5. Complete a risk evaluation of the contributory elements, knowing the “relief factor” (somewhere in the range of 0 and 1) and the “cost of risk management”.
  6. Include the successfully overseen commitments to the bias for each venture risk area. 
  7. Calculate the updated optimism bias %, capital effect of optimism bias, the expense of risk diminution, and the modified capital appraisal.
Estimate, Estimation, Civil Engineering, Cost Management, Whole Life Cycle Costing, Optimism Bias
Estimate, Estimation, Civil Engineering, Cost Management, Whole Life Cycle Costing, Optimism Bias

Why Optimism Bias Is Exploited?

According to the construction industry institute, often projects experience the ill effects of over-optimism, bringing out below-par project performance. Project funding is sanctioned based on the stated project schedule. Through optimism , the desired date is achieved by which funding for the project can be approved.

But the problem comes, when in reality, the project fails to complete at the announced date. This is the most common exploitation of optimism bias. This is a common practice that can be seen in infrastructure development of highways, water rehabilitation, local infrastructure projects, roads structure, and rail construction. 

The huge investments made on infrastructure construction projects, give people immense hopes of economic development in the areas where these projects are intended to build. However, when the same projects are not completed in the given time and fail to provide value, they add disappointment to the hopes of people and waste the state’s money. 

Municipal heads and people want these ventures finished and subsidized as planned, yet the application of optimism bias put the project managers at risk of acknowledging unreasonable suppositions. 

Estimate, Estimation, Civil Engineering, Cost Management, Whole Life Cycle Costing,
Estimate, Estimation, Civil Engineering, Cost Management, Whole Life Cycle Costing, Optimism Bias

How to Avoid the Risk of Optimism Bias?

If you are commanded to convey an essential venture by a certain culmination date, or at an ensured maximum cost, in such a case, the best way to secure your project against optimism bias is to deploy a formal risk management procedure.

While implementing the risk management procedure, go through a list of required points for effective risk management. 

  • Accomplishing expansive partner commitment and contribution in risk evaluation and risk detection. 
  • Risk management procedure permits examination of project presumptions and appraisals by all undertaking partners and not simply project leaders. 
  • The deployment of best procedures to give everybody a voice in risk evaluation and risk detection. 
  • Utilizing lessons gained from comparable projects as a feature of our risk management procedure. 
  • Assure execution of effective risk feedback. 

Risk management is an organized way to deal with rectifying, evaluating, and controlling dangers that arise throughout the strategy, program, or venture lifecycle. It includes a progression of clear-cut strides to help better decision-making through great comprehension of the risks innate in a proposition and their probable effect.

By implementing the risk management process, you can protect your project against optimism however, if you deploy optimism bias, you can adjust the optimism bias in case any project features get affected by it. 

Often, many project elements are impacted by optimism bias, for instance, appraisers will quite often exaggerate benefits and downplay timescales and costs, both capital and functional. It might happen, for instance, through neglecting to reflect completely the odds of cost underestimation or time invades; or by including projections of interest that are excessively liberal.

To review this propensity, appraisers should cause express changes and hence decide an appropriately optimum bias changed NPV for every choice. These changes will expand the quotes, diminishing the projected advantages and broadening the timescales over which the expenses and advantages are accepted to gather, contrasted with the underlying unadjusted appraisals for every choice.

The inclination toward bias in construction planning in civil engineering might be diminished through all-around organized institutional motivating forces and very much planned cycles for project documentation, examination, and endorsement.

Regardless, offices should be fulfilled that the adjustments made are reasonable and legitimate comparable to local experience. They should address a significant attempt to enhance the quality of presumptions rather than discretionary rate changes.


Estimate, Estimation, Cost Management, Whole Life Cycle Costing, Infrastructure.
Estimate, Estimation, Cost Management, Whole Life Cycle Costing, Infrastructure.

Procedure for Optimism Bias Adjustments 

The supplementary Green Book Guidance on Optimism Bias (HM Treasury 2020) gives suggested adjustment ranges and a five-stage way to deal with change. 

  1. Determine the project type(s) to use for instance it includes a standard or nonstandard and structure or civil engineering venture. 
  2. always begin with the upper bound which means choosing the fitting upper worth from the suggested scope of adjustments. 
  3. Inspect whether the optimism (OB) component can be diminished by the degree to which the contributory elements have been overseen and alleviated. 
  4. Implement the OB factor i.e. multiply the applicable expense or advantage gauge by the OB component and add the outcome to the gauge. 
  5. Asses the OB change and decrease it where this is advocated by additional moderation of contributory variables. 

HM Treasury suggests that these changes be founded on information from past projects or comparative activities somewhere else, and adapted to the interesting attributes of the project at hand. 

OB should be evaluated independently for every choice. Various choices can be anticipated to be dependent upon various risks and subsequently various degrees of OB. OB changes should be utilized only to permit for underestimation of expenses and time and misjudges of advantages. They should not be utilized to consider improvements to the project degree or result determination.

Estimate, Estimation, Civil Engineering, Cost Management, Whole Life Cycle Costing,

Optimism bias ended up being broadly acknowledged as a significant reason for unreasonable scheduling for projects. It is exploited by many to get approval for project funds. The Risk Management process helps in securing your project from optimism bias. However, even if you are using optimism bias for the scheduling of your project, follow the adjustment stages to mitigate the risks involved with optimism bias. 

2 comments on “Use, abuse, and misuse of optimism bias in civil engineering, how to avoid it.
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