I have to moderate card sorting session. Our team wants to reorganize navigation in account of financial company's client where he can see information about products and services he uses, conduct payments and transfers, and get new products and services. There is a request from product owner to reduce the number of groups if there will be too many of them.

Should I ask the participant to reduce the number of groups during the session if there are more than maximum I have determined? When exactly should I ask him about it? What if he can't because there are no more groups that can be joined to his opinion?

  • Do you know the difference between open card sort and closed card sort? Irrespective of the type of card sort, I always include blank card just in case the participants want to create new grouping categories.
    – SteveD
    Sep 5, 2016 at 15:53
  • Hello! Yes, i know the difference and i'm going to use open card sort. But I don't know if it is good to limit the number of grouping categories that the user has created. For example, if he has determined 12 groups, can I ask him to form, for example not more than 7 by joining some of them?
    – vio1et
    Sep 5, 2016 at 16:06

2 Answers 2


There is nothing wrong in asking the participants to group the cards into a fixed number of groups, e.g if you told them to organise the cards into 7 groups and you allow them to choose the group names, this has the potential to tell you a lot about their mental models of your solution.

As to how much value this give you, will very much depend on the results, e.g. if 10 people gave you 10 different unique solutions with no commonality, you wont learn much other than your solution means different things to different participants.

The key thing you are looking for are patterns in the results.


Card sorting, like user testing, obeys the law of diminishing returns. The more people you test with, the more you will cover old ground. At a certain point, the extra amount of work involved in moderating and reporting stops being worth it.

Also be aware that testing in groups of users (instead of individual, 1 on 1 sessions) can often place more demands on you as a moderator.

The number of participants you need to involves depends on how many items they will be asked to sort. Any more than 50-70 per person becomes too taxing in most cases. If you have more than this, you will likely require multiple sessions, with each session testing different groups of 70 items.

  • Hello! Sorry, it seems like I should ask question more clearly. I meant grouping categories that the user has formed during card sort session.
    – vio1et
    Sep 5, 2016 at 16:11

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