I just noticed that search results now contain a new query string parameter named "s" with value in the format of s=[a]|[B] where "a" is the search result index and "b" the relevance points, i.e., how relevant is the result to the search term.

For example, this search returns this as the first result:


What is the purpose of adding this to the URL?

When sorting the results by something else (not relevance) the value of "b" above becomes 0 for all the search results, while "a" is still the index.

Also I noticed this happens just here on MSE, so guess it's some sort of test(?).


1 Answer 1


Since the new search was introduced in 2012 there haven't been many changes to the way we score results and in general the search feedback has been good. However, we think we can do better -- therefore, we should.

Thus, as of last week, we have begun improvement work to make our search more awesome. We decided that a good starting point is tracking search sessions -- the series of actions a user makes when performing a search.

For example, we're looking at how many searches one makes before finding a page, and when they do, we want to track how search performed. While we could have done this through a 302 redirect, we decided that this solution would be cleaner and give users the best performance.

This allows us to create search performance reports similar to miniprofiler. They look something like this.


The extra parameter allows us to fill in "Score" and "Rank" in the rows of type "Result Click".

Performance "score cards" like this one are very useful to us: for example if we find that users searching for a particular term are getting bad results, we've found something concrete that we can fix.

Once we have established a baseline measurement, we'll be tweaking stuff and measuring objectively the effects of the tweaks.

  • 1
    OK, fair enough. Would be interesting to know what you fix as a result, over time. :) Nov 3, 2014 at 12:25
  • @ShadowWizard we'll be making the changes quite known, I'm pretty sure. :)
    – Haney
    Nov 4, 2014 at 17:49
  • @Haney heh, I see today you started to add just "?r=SearchResults" to all search results. :) Dec 11, 2018 at 10:23

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