How to design linked filters? [duplicate]

Question

Possible Duplicate:
Best practices for no search results

I always get angry when I refine my search applying filters in any website and I get the 'no results' page. Why do they show me an option that will lead me to a blank page?

I am trying to combine 2 filters. Language and category for an educational website. If I choose english, I would like the system to show me only the categories in english I may choose from. And if If i choose first a category, I would like to have only valid options for the language, do not let me choose a language that has nothing in there!

Any ideas?

Answer 1

I implemented something similar to the design described by @mookamafoob. My filters are divided into three categories, which are related hierarchically. Each filter setting indicates how many values will be available if it is selected; the values adjust dynamically as filters are selected.

The screenshots below illustrate this design:

As you can see, all the counts update when a specific filter value is selected.

Answer 2

A project I am working on currently is facing a similar issue, though here the searches could result in thousands of entities. We are working on allowing pre-filtering in order to reduce the number of results to a manageable number.

The design we are toying around with currently is a section of the search area that says explicitly the number of current results that would potentially come up if they were to hit the search button. For example, the initial number may be that there are 2,500 results before they filter. If they applied filter number 1 (say setting language to Spanish) then the result number dynamically updates to 800 results before they hit search. Then if they set the category filter, the number drops to 25, which is manageable. Then the user clicks search and the results appear, allowing them to sift through them.

Your search features may be smaller scale, but it might be a design option in allowing them to see if their search would yield no results before they actually perform the search.

Answer 3

Use two dropdown boxes, one for language and the other one for category. When one dropdown box is used, the other one will update itself with the list of choices, but the selection remain the same. The default selection for both dropdown box is nothing with some text like "select one."

You actually don't have to care about the current selection becomes invalid if the other box makes a new selection. Because in this case, what is selected will always be valid no matter what the other box selects.