"If something incorrect is repeated enough times, people eventually accept it as correct. In resource loading, many planners repeat flawed methods on project after project, hoping that consensus will substitute for accuracy."
One of the most persistent incorrect practices is loading resources onto LOE (Level of Effort) or WBS Summary activities. While there are specific edge cases where it "works," in a dynamic project environment, it almost always leads to misleading S-curves.
The "Perfect Path" (When it Works)
Imagine 5 activities (A1 to A6) linked with simple Finish-to-Start (FS) relationships. Activity L1 is an LOE that covers these activities perfectly.
When resources are assigned to both the detailed activities and the LOE, the distribution looks identical. This only happens because:
- Relationships are strictly Finish-to-Start.
- There are no gaps between activities.
- There are no parallel activities.
In this rare case, the S-curves will be identical. But in real projects aren't linear.
The Parallel Activity Conflict
Real-world schedules use parallel paths. In the example below, we've added three more activities. While the overall duration and total budgeted units remain equal, the distribution changes significantly.
Because the LOE spreads units evenly over its duration, it fails to capture the "peak" in labor required during parallel tasks. For example, the distributed units for the first two weeks show 67 hours for the LOE, while the detailed activities only require 40 hours.
The Invisible Gap
When a schedule contains a gap (e.g., between A3 and A4), an LOE will still "stretch" across that gap. It assumes resources are working linearly, even when the detailed activities show zero work.
Result: The S-curves diverge, and your Progress Measurement System becomes a work of fiction.
Accuracy is Not Negotiable
Assigning resources to LOE or WBS summaries is a shortcut that sacrifices the integrity of your Project Control system. When your S-curve doesn't match the reality of detailed work, it misleads management and triggers inaccurate decisions.
Discussion
[…] We did discuss one of them (assigning direct resources to LOE or WBS summary) is another article (https://khonopc.com/another-incorrect-resource-loading-practice/). In this article, we will discuss another practice which seems widely used and accepted as correct […]
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