The SWOOP Diversity Index: How is it Calculated?

You may have seen on your personal SWOOP dashboard something called the Diversity Index. You will also see it at the Groups, Team, Business Unit/segment and Enterprise levels where we average the diversity scores across the respective membership.

The information pop-up will tell you it measures the degree to which you are active across multiple groups. The inference is that the more groups you are active in, the more your ‘diversity’ of experience will grow. 

The Diversity Index is presented as a % but in reality that is not quite accurate as you can never be 100% diverse.

In this article, we explain why and how the Diversity Index is actually calculated.

If you look up Diversity Index on Wikipedia, amongst the scary mathematical formulas you will see one of the simpler ones that variously go by the names of Blau or Gini-Simpson Index,and shown as:

Now rather than leave you here to go running to your old maths text books, its use is best illustrated by an example. Let’s say that Joe is a member of a team which accounts for the majority of his online interactions, say 95%; but from time to time he interacts on a site set up to share pet pictures, say 5%. If we want to calculate Joe’s Diversity Index we would apply the formula above:

Joe’s Diversity Index = 1 – ((0.95)2 + (0.05)2 ) = 0.0905 or 9%.
If Joe decided to share his interactions equally between these two groups his Diversity would jump to 50%. 

Now Suzie, on the other hand, grew up in a large family, so sharing equally is ingrained into her work psyche. She is active in 10 groups to which she allocates exactly 10% each of her interactions:

Suzie’s Diversity Index = 1 -  ((0.1)2 + (0.1)2 + (0.1)2 + (0.1)2 + (0.1)2 + (0.1)2 + (0.1)2 + (0.1)2 + (0.1)2 + (0.1)2) = 0.9 or 90%. 

If Suzie had not been so egalitarian and had mixed her allocations among the 10 groups, her Diversity Index would have dropped marginally below the 90% (trust me!).

Now, if Suzie had been equally active in 100 groups her Diversity would only rise to 99%, and she could never quite reach 100% no matter how many groups she is active in.

The following plot shows how Suzie’s Diversity Index would change with the number of groups she is active in, assuming she always spreads her interactions equally:

We can see from this plot the biggest improvements in your Diversity Index happens as you move from being active in a single group to becoming active in 4 to 5 groups. After that, the marginal gain in your Diversity Index in being active in more groups will be much less. Equally ‘sharing the love’ has its advantages, but just being active in more than 4 groups will build your diversity of experience significantly.

Also remember that your Diversity Index will vary with the length of time you select to show your SWOOP data; with the longer the period the more likely your diversity will be higher. So when comparing Diversity scores, do so on periods of the same length of time.