Sorting by Popularity in the OPAC

Within the stock OPAC template there is a new option for sorting search results called "Most Popular". Selecting "Most Popular" will first sort the search results based on the popularity rating determined by the popularity badges and will then apply the default "Sort by Relevance". This option will maximize the popularity badges and ensure that the most popular titles appear higher up in the search results.

There is a second new sort option called "Popularity Adjusted Relevance", which can be used to find a balance between popularity and relevance in search results. For example, it can help ensure that records that are popular, but not necessarily relevant to the search, do not supersede records that are both popular and relevant in the search results. It does this by sorting search results using an adjusted version of Relevance sorting. When sorting by relevance, each bibliographic record is assigned a baseline relevance score between 0 and 1, with 0 being not relevant to the search query and 1 being a perfect match. With "Popularity Adjusted Relevance" the baseline relevance is adjusted by a scaled version of the popularity rating assigned to the bibliographic record. The scaled adjustment is controlled by a Global Flag called "Maximum Popularity Importance Multiplier" (MPIM). The MPIM takes the average popularity rating of a bibliographic record (1-5) and creates a scaled adjustment that is applied to the baseline relevance for the record. The adjustment can be between 1.0 and the value set for the MPIM. For example, if the MPIM is set to 1.2, a record with an average popularity badge score of 5 (maximum popularity) would have its relevance multiplied by 1.2—in effect giving it the maximum increase of 20% in relevance. If a record has an average popularity badge score of 2.5, the baseline relevance of the record would be multiplied by 1.1 (due to the popularity score scaling the adjustment to half way between 1.0 and the MPIM of 1.2) and the record would receive a 10% increase in relevance. A record with a popularity badge score of 0 would be multiplied by 1.0 (due to the popularity score being 0) and would not receive a boost in relevance.