The bottleneck revealed

If you have two or more bottlenecks, you have ignored the real one.
Jan Willem Tromp, Epicflow

1. If you have two or
more bottlenecks,
you have ignored
the real one.
The Bottleneck Revealed
Jan Willem Tromp

2. Project Pipeline Overview

(with start and end dates)
Between 20-40% buffer time
Above 40% buffer time

3. Project Network Examples

(colors represent resource groups)

4. Workload

(from start till end)
Yellow resource group is overloaded,
lacking about 0.5 capacity
Red resource group is underloaded,
about 0.5 idle capacity
Zero level is
maximum load
Average -0.41 man-
hours per hour. 

About half a person
Yellow has 2 

resources
So does Red

5. Workload

(after 2 months of work)
Average -0.25 man-hours
per hour.
Yellow’s overload is increasing
Red is still underloaded, 

but not as much

6. Workload

(after 4 months)
Yellow’s overload is increasing
Red is also getting overloaded
Average 0.05 man-hours
per hour.

7. Workload

(after 6 months)
Average 0.99 man-
hours per hour,

lacking 1 person
Yellow and Red 

are both heavily overloaded

8. Effect on Pipeline

(after 6 months)

Projects are delayed because of overload
Negative buffer time - too late


Between 0 - 20% buffer time


Between 20-40% buffer time


Above 40% buffer time

9. Historical Yellow Graph
Dark blue line - capacity
Light blue line - generated output
Red line - workload, 

dashed line - “ready to start”
Crisis starts
Delivered output:
Above 40% buffer time

Between 20-40% buffer time

Between 0 - 20% buffer time
Negative buffer time - too late

10. Historical Red Graph
Red line (load) exploded and it

becomes a bottleneck as well
Maximum utilization not possible because 

“ready to start” is too low (dashed line)

11. The Bottleneck Revealed
Jan Willem Tromp

co-founder of Epicflow
www.epicflow.com
jan.willem@epicflow.com
If you have two or
more bottlenecks,
you have ignored
the real one.