Should a faceted navigation have an "ALL" filter?

Question

We are having a discussion about faceted navigation. The main question is: Should one of the filters be "ALL" or does an ALL filter create unnecessary interaction and confusion?

Version 1 presents the default view and version 1B shows what happens when the user clicks to filter only Apples. Question 1. Do we need to have the ALL filter? If it presents a better experience, would the filtering behave this way?

Version 2 shows no ALL filter. By default all filters are selected and a maximum number of results are shown. Only by clicking a filter, do the results narrow.

Which ones works better and why? Is it because of the number of perceived steps? Redundancy?

Are there any documents on best practices around the ALL or no ALL filter? Thanks,

Answer 1

There's no one 'right' pattern for faceted search. So it may come down to testing for your audience.

One pattern I see often is to list out the ones that have been selected and show a way to clear them all:

Before selection:

[ ] Apples
[ ] Oranges
[ ] Bananas
[ ] Straberries

After selection:

 X  Oranges

 Clear all fruit options
-------------------------
[ ] Apples
[✓] Oranges
[ ] Bananas
[ ] Straberries

You can either uncheck the item, or use the 'x' icon to remove it. Or you can remove them all with the 'clear all...' option.

Answer 2

The option [All] is different from the other items in the list and shouldn't be included as if it were just another option. Your version 1 looks confusing - it is easy to overlook the [All]-option or to misunderstand the behavior.

You have several options to visually separate the [All] option from the list of menu items, for example these two:

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