Why experience alone cannot fix construction cost overruns

An experienced professional can see risks that a spreadsheet misses. The harder question is how that judgement becomes a repeatable practice that the next person can learn.

My MSc dissertation explored Bhutan’s readiness for international cost management standards. One theme was the relationship between professional experience and reported cost overruns. More experienced respondents tended to report fewer overruns, but experience accounted for only a limited part of the variation in the analysis.

That is a useful starting point for discussion. Experience matters; it also needs a system through which it can improve the work of an entire team.

Make judgement visible

Consider a senior estimator who allows extra time for difficult access. If the allowance appears only as a percentage in a workbook, a younger colleague sees the number but may never understand the reasoning. Was the concern road width, unloading space, seasonal disruption or the distance from the nearest supplier?

Recording the reason, the evidence and the conditions under which an allowance applies makes the judgement reusable. It also makes it possible to challenge that judgement when the circumstances change.

Close the loop after delivery

A completed project can teach the next one, provided its records allow a meaningful comparison. A final cost above an early estimate does not explain itself. The difference may reflect additional scope, a design change, a pricing assumption or an issue during construction.

My practical recommendation is to compare the estimate with the outcome on a consistent scope basis, then record the reasons for material differences. Keep a separate record of approved changes. Otherwise, a project that expanded substantially can appear to be an estimating failure, while an underdeveloped estimate can hide behind a general explanation about market conditions.

Give mentorship a structure

The expert consultation in the dissertation highlighted technical capacity and training needs. A useful response is to make mentorship part of the estimating process: pair an early-career professional with an experienced reviewer, discuss the assumptions before tender, and revisit them after the project.

Three habits would make a practical beginning:

• Keep an assumptions register that explains the basis of the estimate.
• Review the major cost risks with someone who did not prepare the estimate.
• Carry a short record of lessons from completed work into the next cost plan.

These are proposed working habits, rather than interventions tested by the dissertation. Their purpose is to help professional experience accumulate in the organisation as well as in the individual.

Read the evidence with care

The research used self-reported practitioner responses and expert consultation. An association between experience and reported outcomes cannot establish that experience caused those outcomes. The study also did not independently audit project accounts.

The question worth pursuing is therefore practical: how can we make experienced judgement more transparent, more teachable and easier to evaluate?