USING THE SCRUM EFFICIENCY INDEX (SEI)TO COMPARE PERIODS WITH VARYING STAFFING LEVELS

In Scrum, when we set up a time period, we keep track of velocity so we can compare how fast we are moving. This is affected by a few things, velocity and capacity. Capacity is also affected by available productive hours. So what we are really trying to derive is how productive is each hour spent in the scrum environment.

Here is the method I used to calculate the answer to that question:

Assumptions:

1. All velocity points are equal, for example, a Fibonacci sequence must always follow the same scale in relationship to time, see Table 1. In keeping with Agile principles, close enough is good enough. We don’t pay for precision when buying close enough costs nothing. You will create your own scale, the trick is to remain consistent.

TABLE 1: CREATE AN ESTIMATE TO TIME RELATIONSHIP

Estimate 1 2 3 5 8 13Hours Represented .5 1 5 10 20 40

2. Available Productive Hours is any time spent in the Scrum or working on Scrum work. This will vary from person to person for each Scrum for each period.

SEI ¿ v÷ Σ(ProductiveHours)Example:

Period 1:v = 26Prod Hrs = 300

.09 = 26/300

Period 2:v = 50Prod Hrs = 120

.42 = 50/120

To compare these two periods, subtract the later period from the earlier period and divide the result by the later period:

.42-.09 = .33

.33/.42 = .785

This shows a 78% improvement in the efficiency of the process.

Charles Cooper, MA, MBA, PMP, ACPLean Six Sigma Master Black Belt

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