I read this somewhere that Nominal categorical data makes sense in a (stacked) bar chart, but not in a (bivariate) line chart AND Interval data makes sense in a bivariate line chart, but not in a stacked bar chart.Can anyone explain me the above statements with some sort of example ?

Source(Look at the end of the webpage under Exercise section)


1 Answer 1


Here's a small example of three different chart types:

stacked bars, side-by-side bars, and overlaid lines.

enter image description here

All three are showing the same 6 Y values (3 red and 3 blue), but each has its own connotations. Most basically:

  • The bars are distinct objects, reinforcing that A, B, and C are categorically different without any other states between them.
  • The lines have a connected sequence and suggest a continuity of values. For instance, line suggests you can guess the Y value for x=15, say, by line position above the tick for 15.

The stacking suggests that the sum of the blue and red is relevant.

Using bars for continuous values is rare, but it's not uncommon to use lines for categorical data. In those cases, the reader has to look past the continuity connotation and see only the connectedness aspect of lines and the categorical "profile" for comparison.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.