ENR has a webinar on October 25th relating to how CPM and Lean Construction planning and scheduling conflict or complement each other. The webinar will be available for view for an entire year until 10/25/17 and you can find more information here.
At the Construction CPM Conference 2015 our Great Debate had the two systems competing. My thoughts then and now are we have a two-stage process. CPM was neither intended nor designed to provide exact dates for work to be performed. Even performance dates for work on a “critical path” are expected to be approximate and subject to final control by the project superintendent and her team. For non-critical work, the CPM analysis suggests two sets of dates relating to “early” and “late” performance. Plotted out we have the double S curve of long range planning.
The use of CPM provides two big advantages. By planning the logic of the entire project – including those pesky details near the end – we can determine now whether it may be advantageous to spend a little more now to avoid spending a lot more later. And by tracking current progress on a (best case) weekly or (worse case) monthly basis, we can compare the actual to the anticipated and revisit that spending question.
Now we can consider issues of Lean Construction. It may be better to bring in a second dozer to clear the site now rather than a second crew to fine tune the HVAC later. But if the HVAC equipment will not be delivered until the tenth month and work may stop until it is rigged into place, such a decision may be a waste of investment.
Determining how far the Lean Team will look ahead is also a function of the complexity of the project, of the CPM logic and of the risks of change of scope, conditions and productivity.
But don’t just take my say so. Go watch the webinar with input both from consultants and those working in the trenches.