Human Effort Is Not a Number: Rethinking Productivity in Planning

“I do not believe in applying human efforts into numbers or productivity rates. People are not like machines.”

This has been my perspective for a long time—and the more I work in planning and project control, the more I believe it’s true.

One of the most difficult questions we face as planners is: How many man-hours do we need for today’s tasks? Yes, there are standard methods. The usual process is to compare actual quantities with average productivity rates to calculate how many workers are needed within a given time frame. It sounds logical—but is it truly accurate?

Let’s be honest: productivity rates are useful, but they’re also flawed—because they assume that people behave like machines.

Machines have consistent output. They operate within controlled environments. Humans don’t.

A worker can perform at full efficiency today and slow down tomorrow—under the same conditions—for no apparent reason. Maybe he didn’t sleep well. Maybe he’s distracted. Maybe he's just human.

This variability can never be fully captured by a productivity rate. It can only be approximated. And no matter how perfect your calculation is, real-world human behavior will challenge it.

So what should we do?

The answer is balance. Approach the best estimate using available data, but always leave room for tolerance. Don’t build plans that rely on perfection. Build systems that can absorb variability. Accept that human effort is dynamic and unpredictable.

Because planning is not just about numbers—it’s about understanding the people behind those numbers. And when you plan for people, not machines, your forecast becomes smarter, not just sharper.