If you've ever looked at rank log or the ExplainRank.aspx page, you may have noticed that term frequency scoring is only a portion of the total rank score. There are many other relevancy features which contribute to rank scoring. Among them are "click events". Click events measure the interaction, or lack of interaction, between a user and the search results. The information is then used to boost or de-boost documents accordingly. There are four "click events" which contribute to relevancy. They are, as named in the ExplainRank.aspx page: QueryLogClicks, QueryLogSkips, LastClicks and EventRate. The rank log, respectively, names them QLogClicks, QLogSkips, QLogLastClicks and EventRate. There is another event named ClickDistance, but technically it has nothing to do with click events. ClickDistance is a boost based on the distance or number of links (could be thought of as clicks) between a document and an authoritative source.
Here are definitions for the four click event relevancy features.
- QueryLogClicks - A boost based on how often a document is clicked on in search results per query.
- QueryLogSkips - A de-boost based on how often another document of a lower rank is clicked on, instead of this document, in search results per query.
- LastClicks - A freshness like boost based on the last time this document was clicked on in a search result.
- EventRate - A boost based on how often a SharePoint document is clicked or viewed (not in search results).