Resource Allocation 101: Spotting Overallocation Before It Becomes a Problem
Overallocation almost never gets caught by looking at a task list. Here's how a resource workload heatmap surfaces it before the deadline does.
Overallocation is one of the easiest problems to create by accident and one of the hardest to spot from a task list. Every individual assignment looks fine in isolation: it’s only when you add them up per person, per week, that the problem shows up. And by the time it shows up as a missed deadline, it’s too late to do anything about it except apologize.
Why task lists hide the problem
A task list tells you what’s assigned to whom, one row at a time. It doesn’t tell you that Sarah is assigned to four tasks that all run through the same two weeks at 50% allocation each, which adds up to 200% of her available time on paper, without a single row looking unreasonable by itself.
You’d have to manually cross-reference every assignment against every other assignment for every person, for every week of the project, to catch that. Nobody does that by hand reliably, which is why overallocation tends to surface as a surprise rather than a plan.
What a workload heatmap does instead
GanttPM’s Resource view assigns people to tasks with an allocation percentage, then rolls those percentages up per person, per time period, and shows it as a heatmap. Weeks where someone is at or under 100% read clearly. Weeks where they’re over 100% are visually distinct: the problem is visible at a glance, not buried in a spreadsheet you’d have to build yourself.
Because this is the same task data driving the Gantt chart, the heatmap updates the moment you reassign work or shift a date. Move a task two weeks later in the Gantt view, and the Resource view reflects the new allocation immediately, with no separate resource-leveling report to regenerate.
Fixing it once you see it
Seeing overallocation is only useful if acting on it is easy. Once a heatmap shows someone’s overloaded in a given week, the fix is usually one of a small set of moves:
- Reassign part of the load to someone with slack in that same period.
- Shift a task’s dates: if it has slack in the CPM sense (not on the critical path), moving it doesn’t cost the project anything.
- Reduce the allocation percentage on one of the overlapping tasks if the work genuinely doesn’t need someone full-time in that window.
The heatmap doesn’t make these decisions for you, but it makes sure you’re making them before the deadline, when you still have options, instead of after, when you don’t.
Where to find it
The Resource view is available on every GanttPM project (local or Cloud) alongside Gantt, List, Kanban, and Calendar, all reading the same assignment data.