Filtering Best Practices

Question

What are the best practices for filtering out a big list?

1. Keep all filters wide open all the time

OR

2. Narrow filter values down as I add a Filters somewhere else?

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For example let's say I have a List with thousands of Students.

The Columns I can Filter on are: First Name, Middle Name, Last Name

I have 100 students with the last name Anderson and 100 students with the last name Smith.

Now I go to my Last Name column and Filter by both Anderson and Smith. When I go to the First Name column to add an additional filter, should I see the thousands of First Names OR should I just see the 200 First Names that belong to Anderson and Smith?

Answer 1

You should see the 200 First Names that belong to Anderson and Smith.

The users are in this mode of narrowing down the result and you should help them to narrow down the result to their specific needs.

It's the most common practice for example e-commerce sites (see this example of how Best Buy does it) and therefore the users will find it most natural and are most used to it. Here is a study by Baymard on the subject.

Additionally, you should clearly display what filters the users has activated (usually with a list of tags) and add a Clear-button to help the users start over if they decide to filter the list by First names instead.