research - Is 10 search results per page the best?

When there are a lot of search results they often are paginated. Most search engines I know show 10 results per page. I guess this was born out of an easy technical solution or habit. But I don't know if it is still valid or usable.

Why not 8, or 11? Is 10 an especially easy to remember amount? Or do 10 results fit nicely in two views (one times PageDown) of a page?

For example, I know Google changed the way Google Images work to continue to load new pages when scrolling instead of clicking to a next page. As far as I remember they did this because they noticed people checked far more results (say up to 15) as opposed to the normal/web search (1 to 3) before they were satisfied. Thus it would be good if you could easily see more than 10 results.

Another example. Some search results show a lot more. For example ticket systems, CRMs, email's inboxes, etc. The results fit on one line so it makes sense to make more use of the available space. Results can go from 20 to 50 to 100.

Currently I'm working on a website where you can search for photographers^[1]. So we show of their photos. Each search result is quite high in pixel height. Meaning you have to scroll a lot more to get to the bottom of page 1 as opposed to Google. Would it be worth to have less results just because of this?

To sum it up:

• Is there a reason why search results are often split by 10?


• Are there rules for when to show more or less? (i.e. type of media, height, etc.)


• Is there any research done on this topic?

I'm not specifically looking for only research references, I love educated guesses and smart thinking.

Answer

No.

The amount of results per page should depend on:

1. 
   

   The display size of each result - the smaller the result the more you should show per page e.g. from small to large: thumbnail, one line, multi line, large image, ...

   
   


2. 
   

   The window size - the larger the user's window is (or device's screen if in fullscreen mode) the more results you should show. Showing 10 results and leaving half the window unused is a very bad practice (which I regret I have seen).

   
   


3. 
   

   The ease of scrolling up/down vs. clicking on next/prev - it is usually easier to scroll up and down then to click on prev/next over and over. Scrolling up and down only requires clicking on the keyboard page up/down keys or up/down keys for small changes. Or, using a mouse - scrolling with the wheel. Clicking on prev/next, requires scrolling to the bottom, moving the pointer to the arrow, clicking on it and then repeating the entire process over and over.
   
   Both processes can be optimized:
   

   
   
   
   
   • Scrolling by adding a next/prev button between every N results (that jumps within page).
   
   
   • Prev/Next by adding accelerators (e.g. making page up/down keys turn page). Accelerators must be known to users and page must not go beyond window, otherwise user will need to scroll down and then user accelerator.
     
   
   
   
   


4. 
   

   Response time - if fetching results takes a noticeable amount of time regardless of number of results, bringing more results per page will save the user time. If fetching results takes a noticeable amount of time per result, but there is no constant time per page, then the less results per page, the faster it will seem to user.
   Ideally, both should take as little as possible and this shouldn't be a factor.

   
   

A good example of the ease of scrolling vs. paging is Google Images, where you can now see more results by scrolling down and clicking on "Show more results".