Expert Witness Journal Issue 65 February 2026 - Flipbook - Page 31
Establish causation?
Performance Analysis
Having determined there has been a loss of
productivity – and therefore higher costs – the
next step is to establish the cause of the loss. In the
earthworks example, the cause was the change of
the stockpile location. The Employer was to provide
an area of land for the stockpile but once the project
commenced the location was not available and an
alternative was provided.
What I have described so far is about recognising
issues with productivity to help in recovering
additional costs where it is appropriate to do so and
as such, it is often carried out after the event – indeed
it is often an afterthought and only recognised
once the contractor realises it has lost money on
the project. However, performance analysis is also
a helpful and transparent tool to help manage and
deliver the project.
This is quite straightforward but, what if the
contractor’s planned outputs and resulting budget
was over ambitious in the 昀椀rst place?
When the project programme is updated, it is
normal to record current progress (% complete) up
to the date of updating. The programme is then
rescheduled, and the completion date is forecast.
This approach - which is common practice – assumes
the remaining work will be completed within the
planned remaining durations.
What if the contractor always required 3 machines
to carry out the work but only based its tender on 2
machines?
I expect many of you will have been in a tender
昀椀nalisation meeting where the director ‘requests’
that time, money or both are ‘stripped’ out of the
‘realistic’ tender programme and sum to win the
work! I know I have!
However, a question to be asked is how long did it
take to achieve the current work completed?
For example:
Activity 1 has a duration of 20 working days
(diagram 1).
It may be that the Employer change did cause a loss
of productivity, but this was further exacerbated by
the contractor’s own culpable performance.
After 4 weeks, the programme is updated, and a
measure of the work shows that 50% of the Activity
1 – which started on 06 May - has been completed
(diagram 2).
Below, diagram 1
Below, diagram 2
The forecast e昀昀ect is Activity 1 will 昀椀nish on 13 June,
and the project will be completed 2 weeks late.
However, a closer look at the critical driving activity
tells us that the contractor has taken 18 working days
to achieve 50% of the work which was planned to
take 10 working days.
Below, diagram 3
If we compare the actual productivity to the planned,
we can better visualise the performance achieved
for Activity 1 (diagram 3).
Using the average productivity rates to date we can
forecast the 昀椀nish date for Activity 1, which in this
example is 30 June (diagram 4).
EXPERT WITNESS JOURNAL
29
FEBRUARY 2026
