We have all got kind of used to all kinds of things requiring information they have no reasonable need to.

  • Eg a forum requiring your phone number, address and occupation.
  • A raffle requiring more or less your life-story.
  • Almost everything requires you to give your gender, when that has literally nothing to do with the service being offered.

The reason these are asked for is generally pretty obvious -- it is market research. Though I think there is also a aspect of monkey-see monkey-do. Everyone else did it why shouldn't I?

StackExchange (and other things that let you sign-in/up with only a OpenID) are a refreshing change.

Another example, not online, I am part of a organisation that has a requirement for all members to submit a membership form each year when they renew. One of the services our organisation offers is book borrowing. To borrow a book, a book borrowing form must be completed. Now there were two view points on what should be on the borrowing form:

One said, we need the names of the book, the borrow dates, and there name (or organisation is small enough this is a unique identifier), and their address and phone number. Then if we need to track them down because the book is over-due we can track them down and get it back.

The other argument (mine), said that we just need there name, the borrow dates and the book dates -- none of their details. We don't need the details -- they gave those to us when they submitted their membership form. The reasoning behind this is that it would be a better user experience if it was shorter. Thus would be more likely to use the service, and also to actually submit the borrowing form -- instead of just grabbing the book without filling in a form (which has happened alot historically.)

I'm looking for a term to describe this principle in UX design, so I can research it further. The "Minimise information required/obtained from users" principle.

I'm sure there are other side benefits from following the principle, like minimising the amount of privacy concern overhead in tasks (Such as the need for a Clear Desk Policy)

  • We call it 'lowest barrier to entry'
    – user50747
    Commented Jun 20, 2014 at 19:53

2 Answers 2


The minimal information might be called mandatory information in the context of government organizations because they have to comply with personal and privacy information that mandates only the minimal information is required to complete tasks/transactions. However, I think the lines are rather blurred as you say, when there are no clear guidelines and it is a matter of personal opinion.

In the same way it is like describing the minimum/critical path, which is the shortest or most important process/steps for the user to accomplish a task.


There are several terms from related fields that come to mind.

Data minimization is the wording used by the GDPR (General Data Protection Regulation) in the context of data collection. This basically means "collect the bare minimum needed for the purpose, nothing else". This approach preserves the privacy of data subjects (i.e., the people whose information is collected), as it reduces the possibility that the company that collected the data will know more than they actually need to get the job done. This is a well-established legal term now.

Need to know is a term used by the military (but also law enforcement, security and probably terrorists too), when determining how to disseminate information. By not sharing it with everyone, you minimize the risk of a leak or the risk of compromising your operation. For instance, when someone is captured as a prisoner of war, the enemy won't be able to get any useful intel out of them, because the captured person doesn't even have such information.

Information efficiency is a term from information theory that I find very useful. Just like in the case of computing the efficiency of an engine (where you consider "total work" and "useful work"), you can compute the efficiency of an interface by considering "total work" (i.e., everything the user has to provide) and "useful work" (i.e., what is actually necessary). When total work far exceeds useful work, it indicates that a significant amount of the users' input is actually wasted. For a more detailed analysis of how this technique is used in HCI, have a look at ISBN 0-201-37937-6, "The humane interface" by Jef Raskin.

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