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I have several business units with a different amount of customers and we are tracking how many of these customers completed a requested task. I want to track who is performing the best but a simple % improvement will be skewed based on the total customer count, as a 1 task completion improvement in Chicago is weighted more than an improvement in Los Angeles. What would be the best way to calculate improvement statistatically?

Business Unit Customer Count Task Completed Baseline Task Completed after a Month
Los Angeles 2,742 2,648 3,200
Boston 602 148 250
Dallas 1,006 198 450
Chicago 367 98 250
Miami 4,538 1,396 2,100
Seattle 7,001 3,207 5,000

I tried a simple % calculation but smaller customer bases are rewarded more than larger customer bases.

Jake1204
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1 Answers1

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You're correct in pointing out that a simple percentage calculation may not accurately reflect the true improvement when dealing with business units of different sizes.

To address this issue, you can use a statistical method called "standardization" or "z-score normalization".

1.Calculate the percentage improvement for each business unit: Percentage Improvement = ((Task Completed after a Month - Task Completed Baseline) / Task Completed Baseline) * 100

2.Calculate the mean and standard deviation of the percentage improvements across all business units.

3.Calculate the z-score for each business unit's percentage improvement using the following formula:

Z-score = (Percentage Improvement - Mean of Percentage Improvements) / Standard Deviation of Percentage Improvements.

Business units with positive z-scores are performing better than the mean improvement, while those with negative z-scores are performing below the mean improvement.

Buddhima Kaushalya
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  • Thank you! Figured I had to go back to Stats 101-- couldn't find my old textbook. Appreciate the help. – Jake1204 Jul 27 '23 at 21:14