Comparing to Historical Averages

Last modified: July 15, 2019

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Comparing to Historical Averages In Progress Overview

We work with hundreds of companies who are trying to get valuable insights out of their data. We see companies comparing the success of their product or feature as compared to a historical average.

We want to show how comparing to a historical average can be misleading. Is the past 6 months an appropriate window? Were there any trends in the data prior to our test? Then we want to cover how to create SQL queries to compare to historical statistics. Lastly we want to walk through interpreting historical statistic comparisons.

Outline + Learning Objectives

The problem with historical averages

  • Describe why a historical average can be misleading
    • Describe how it may hide a trend in the data

Create appropriate historical comparisons

  • Create SQL queries to compare against previous set of months
  • Create SQL queries to compare against the same month last year

Interpret historical statistics

  • Differentiate between analyses that use historical comparisons appropriately and ones that do not

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