MAKING PRODUCTIVITY VISIBLE TO EVERYONE
Accuracy of estimation in construction can be viewed from two different perspectives: takeoff or
or “exactness accuracy” and “performance based accuracy”.
While takeoff accuracy is based on a correct count of material from careful review of the drawings,
performance based accuracy is where the estimator allocates labor-units based on historical performance.
It is here where the estimatorís art of estimation will shine. EAE allows us to improve performance based
estimation accuracy through the correct interpretation and recognition of labor performance in the field
the opportunity to win more jobs.
Only by improving performance based estimation accuracy through the correct interpretation and
recognition of labor performance in the field the opportunity to win more jobs will increase.
Using EAE® to Determine Performance based Estimation Accuracy
Estimators typically work with an average performance of the cost codes over time. However, using
averages of data without considering the range and statistical outliers skews the results. To use the
available data correctly, factors such as geography, cost code mix, allowance for pre-assembly, and type
of construction need to be considered to make confident decisions based on more than just averages.
Good estimators do this intuitively; EAE® allows those “gut feels” to be supported by
EAE® allows jobs to be identified according to a number of criteria. First,
jobs are selected based on relevant criteria (size, type of work, crew, etc.) From there, an analysis of
the estimate vs. final performance can be made in terms of hours or cost, including the following:
- Data for estimated vs. actual hours or cost per cost code, per job in the category set selected
- Graphical comparison of estimated vs. actual hours or cost, overall and per cost code
- Comparison of cost code performance between all jobs within the selected categories, and a
particular job in the same set
- Interquartile range (IQR) analysis of the cost codes in the job set, which gives the spread of
the selected jobs’ performance and the position of a particular job within that set
- Timeline charting to track changes over time
- Risk analysis based on the historical differences between jobs
The analysis of data for estimation accuracy can be enhanced by improving the quality of the data.
The data analysis is only as good as the data upon which it is based. The closer the measurement
is to the actual work, the more useful it will be as input to the estimation process.
labor productivity, and provides feedback from the field on a regular basis of Construction Put in Place (CPIP).
JPAC® can provide invaluable information
to estimation about the actual installation efforts. Using trend monitoring, estimators can review what
impacted the job at various points and take those impacts into account for a similar estimate.
the obstacles that hamper the field’s short interval scheduling. These causes for productivity loss
could become magnified in the view of JPAC®,
and can also be useful for estimation to understand what daily obstacles should be considered on similar jobs.