#10 Usability Testing — What’s the right number of participants?

Hey, how are you? I was a little occupied the last couple of weeks. I was learning about how to build a gaming PC and was also into understanding the esports scene in India. That is the reason I couldn’t write Newsletter.

Currently, we are carrying out a usability testing exercise at Zeta and I learnt a few important numbers. I always used to wonder how many participants should we recruit for usability studies?

I came across these two articles by NNG, that gave a good idea:

https://www.nngroup.com/articles/why-you-only-need-to-test-with-5-users/

https://www.nngroup.com/articles/quantitative-studies-how-many-users/

Summary of the articles

If you are interested to find out if the user can complete the flow easily or not, you need to test with 5 users. If you want to test the degree to which users are struggling, you will need 20 users for the test. Anything beyond this has a diminishing return.

20 user tests are generally expensive and should be kept for critical designs in the products. 5 users can tell us if a flow is working fine or not and can give us some qualitative insights. A 20 user test is required if you want to measure something, like how long will it take the user to complete a task. Most of the times data analytics on live products is a much better option than quantitative studies on prototypes.

For companies who can afford 15 users, One efficient strategy is to iterate 3 times. Design — Test with 5 users — Fix Issues — Test with 5 users — Fix issues — Test with 5 users — Fix issues.

That’s all folks! Have a good day ahead! 😃

Regards
Bharat Apat
https://www.instagram.com/apat.bharat/