The Effectiveness of Improvement Measures

In my post Measures for optimizing Productivity I pointed out some key areas with a high leverage for productivity improvements. In business often the cost-to-benefit ratio is another important criteria to find the right measures.

Diagram 1

Thereby the breadth or scope of a measure plays an important role: How large is the percentage of the total development process being affected by the measure? Example: An action which doubles the productivity but only in a part of a project which accounts for 50% of the total effort (blue area of diagram 1) increases the productivity of the overall project only by 33%. Explanation: Productivity and effort are reciprocal, i.e. increasing the productivity results in a reduction of the effort and vice versa (see: Measuring Productivity in Software Development). The mentioned action reduces the effort in a sub-project with 50% of the total effort by 50%. This results in an effort reduction of 25% for the overall project, i.e. 75% (3/4) of the effort remains. Due to the reciprocity the productivity is 4/3 of the original value, which is a raise of 33%.

Diagram 2

The productivity improvement being effective after multiple actions have been performed depends of how these actions influence each other. As long as they are independent the resulting productivity can be calculated by setting each of the according effort reductions in relationship to their percentage of the total effort. Thus leads to the remaining effort and hence to the improvement of the productivity. Example: Diagram 2 shows how two different measures increase the productivity each by 100% in completely different areas of a project (blue and green), each area accounting for 25% of the total project effort. The resulting effort is in total 3/4 of the original, i.e. the productivity is 4/3 and has been increased by 33%.

Diagram 3

For improvement measures affecting the same area and influencing each other their effort reductions can be multiplied. Example: Diagram 3 shows how two actions increase the productivity each by 100% (halves the effort) in the same area (blue) accounting for 25% of the total project effort. The resulting effort in the affected area can be calculated by 50% * 50% = 25% (a quarter) of the original effort, i.e. the total effort of the overall project is now 13/16 of the original and therefore the productivity 16/13. The productivity has been increased by about 23%.


The following lessons can be drawn from these examples:

• Improvement measures are more effective the higher the effect on the entire process is (percentage of the total effort).
• Any productivity improvement resulting by multiple measures depends on how these measures influence each other. As a general rule: The more independent they are, the more effective they are in total. Unfortunately this is difficult to predict. Usually only a range can be determined for the expected improvement.