So on Sunday, I posted a comic about how goofy it can be to average long-term data to describe current state measurements. Imagine my surprise this afternoon upon checking the RSS feed to see this new comic on xkcd:
While this comic tackles a different problem with averaging than does my own post, it seems like concerns with averaging as a description of data are on the minds of many. (To get an idea of the scope of the discussion, check out the conversations happening in the comment boxes on posts by Frank Noschese and David Wees, respectively.)
Our comics highlight two different but very real issues with trying to describe such a complex thing as learning with such a simple thing as one averaged value:
- When we take values that do not match intended outcomes (a student’s knowledge, understanding, and skills acquisition) and average them together, the new number does not somehow suddenly describe outcome achievement.
- Even if we do happen to measure the outcomes described above, but those measures are taken over time and then averaged together, the new number does not somehow suddenly describe current state.
Have you seen any other visuals that help to describe these problems with averaging data?