I would like to test how 2 different fonts (mostly for numbers) would affect performance of operations team. At the moment I have a hypotheses: "By changing font from A to B cognitive load of ops team will increase resulting in errors/slower performance"

And I will measure errors and time on task. Also ask them to provide some qualitative feedback about the use of the system. I have access to at least 5 people that are actually using the product. And are able to provide me with feedback.

Is this a correct approach? Or is there a better way of testing for small changes like font and how it impacts performance

1 Answer 1


The methodology is good, although you can design much more valid experiment that focuses only on reading or making calculations with the digits (see below).

But why would you think you will find any difference if you change the fonts? In my opinion, you will find difference only if your current font has really bad legibility, like alphabetic fonts. Otherwise, if your current font is sans-serif I don't see any sense to waste your time testing this. You will probably find no difference.

If you want to design valid experiment you want a task of reading digits or mental arithmetic. Then you need at least 15 people to take the test and should measure their react times, as this is an inference measure of mental workload. Then you will see in which variant you will have the fastest reaction times. The downside of this experiment is that is time consuming, and in my opinion you will likely find no difference between the two fonts if they are from the same font family.

  • 1
    This was mentioned by one of our employees (not ops). We used to have Arial and now design team decided to move to montserrat light. In my opinion it does make it harder to read but I need to have a proof to be able to persuade the team to change. I was thinking just asking ops but I don't want to lead them.
    – Igor-G
    Jun 16, 2016 at 9:16
  • Well if your app is mostly about reading and calculating, then this is an important research you should do. Else, its not. However, I think both font faces are ok, so don't waste your time in this while you can research problems that might have much bigger impact on your app. Jun 16, 2016 at 11:11

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