How many participants do you need?

According to the NN Group, the golden number of participants for usability studies is 5. The exact number of participants you need for your study will depend on the nature of your research:

• Quantitative studies require a minimum of 20 participants
• Card sorting studies require at least 15 users per group
• Eye tracking studies require 39 users to generate stable heatmaps^[1]

Recruiting more participants does not mean better data quality in UX research because the focus is usually on gaining qualitative insights. Besides, inducting more participants leads to more testing costs and reduced ROI, making it a redundant exercise.