A lot of sites use an additive filtration system while there is also subtractive now is used.

A difference in an interaction method: Additive First of all you need to choose a set of the options necessary to you and call to filter button,

Subtractive This method based on consecutive liquidation of unnecessary results.

The additive model often conducts to a "zero searches" with a relevant data based on features of interaction of the user.

Why the additive form of a filtration is used everywhere, though subtractive leads to the necessary result much faster and there is no zero searches possibility?

  • One possible threat you should also consider is the number of filters too and if these filters mix and match both methods. Feb 21, 2012 at 17:41
  • Can you give an example of a site with "additive" filtering?
    – dnbrv
    Feb 21, 2012 at 19:33
  • carsales.com.au tripadvisor.com/Restaurants & many others Feb 22, 2012 at 6:31
  • I get what you mean but your question is currently worded too broadly and is a candidate for closing ("what do you think" questions aren't allowed). Please see the FAQ and rephrase it - I'll explain everything.
    – dnbrv
    Feb 22, 2012 at 18:16
  • I have formulated the question differently. Сlosed theme won't allow neither me nor the rests to whom this question is interesting, to come nearer to the answer. If you have understood about what there is a speech - could you give some examples of sites with subtractive form of a filtration? Feb 22, 2012 at 19:04

2 Answers 2


Well, if pulling some starting data for the beginning of a subtractive process isn't too intensive I think that it has some advantages.

With a subtractive process the user is presented with more information about the data. This information might help them decided how to filter and narrow down on what they really want. This way users might have less of a chance of hitting a false negative.

In an additive filter, if a user picks the first filter that they think will show them what they want and nothing is returned, they might assume that nothing is there. But in a subtractive filter if the user starts out seeing some data and some of it looks like it could be close to what they want (or it looks like there's enough data... perhaps shown through pagination) they might be more inclined to try other filters.

In general, I think that looking at a blank slate can be a little paralyzing for users. Subtractive filtering gives a starting point.


A substractive filter makes sense when you have a limited amount of results to start from (e.g. filter for finding email in Gmail and Microsoft Outlook).

An additive filter makes sense if you are searching in a near infinite range and want to bring back a finite amount of results (e.g. default in Google search).

The most accurate results are received by allowing any combination of the two, along with boolean expressions and search fields e.g.
ux AND (stackexhange OR "stack exchange") AND NOT(stackoverflow) AND filetype:html

However, I believe most users don't use advance search expressions.

  • All is true, I agree with you. From your answer followed that subtractive system will perfectly approach for e-commerce and car-sellers websites6 cause number of results is limited. But the majority of them use additive model on practice. Feb 22, 2012 at 19:51
  • @danieleckmann The number of results in an e-commerce database is usually much larger than in your inbox and just showing the first 10/20/100 without any filter or sorting wouldn't help users much. I am more of an advanced search user though :-) Feb 22, 2012 at 23:48
  • I managed to find only one car-sales website with subtraction filtration model. Many computer e-shops already use it, including Amazon. Here's another question with additive filtration method ux.stackexchange.com/questions/17605/… . It's hard to find smth there for me cause too much Zero results. Feb 23, 2012 at 10:12
  • @danieleckmann If you start out with browsing by category (e.g. TVs only or TVs+Computer Screens only) or some other catalog system, then you start out with meaningful results and can filter from there. If you start out with any possible product type, then asking for at least one filter before presenting results may make sense. Feb 23, 2012 at 11:27

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