Data Mistakes Even Children Can Find

Note: I am happy to announce a new  addition to my blog, Prithi Srinivasan, presently a fifth grader. Look for her thoughts and analysis on data, coding, probability and economics.


Take this graph on iOS book sales, for example. Look at it carefully.

Can you spot any mistakes, because I sure can: three of them, and I’m only a fifth grader.

The big revealment:

1. The first mistake is that between 0% and 14%, there should be a break, as all the values other than 0% to 14% increase equally.

2. There was one exception to that last statement. Between 15% and 17% there has to be a 16%— not a break.

3. It should be a bar graph! Line graphs are meant to show differences over time–as one big concept. This graph ought to be a bar graph because it is showing the percentage of book sales per day. It shows separate concepts.

If they get paid to create graphs with many errors, then I should get paid for fixing those errors.