Filter scoring

As well as refining results, you can use filter scoring to rank records according to how well or poorly they match a set of filters. Scoring applies numerical settings to filter values, making some filter values more important than others. Records with the highest filter values sit at the top of the results list.

Consider the case of stock portfolios in which companies are scored according to their monetary significance. You could use filter scoring to rank Google higher than Facebook. For example:

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index.search('', {
  filters: "(company:Google<score=3> OR company:Amazon<score=2> OR company:Facebook<score=1>)",
});

The result is that records with Google stocks sit at the top of the list, higher than Amazon and Facebook.

How scoring is calculated

Filter scores are integer values from 0 to 65,535.

Default scoring

In the preceding example, any portfolio containing all three companies (Google, Amazon, and Facebook) would score 3, as the overall score is based on the highest score. In other words, by default, there is no accumulation of individual scores.

Accumulating scores with sumOrFiltersScores

You accumulate scores by setting the sumOrFiltersScores parameter to true. In the preceding example, any record with all three companies would have an overall score of 6 (3+2+1).

If sumOrFiltersScores is false, the default, the system uses the default scoring method: taking the highest score. Using the preceding example and a query filtered on Google and Amazon with sumOrFiltersScores = false returns a score of 3 (google(3) > amazon(2) > facebook(1)).

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index.search('', {
  filters: '(company:Google<score=3> OR company:Amazon<score=2> OR company:Facebook<score=1>)',
  sumOrFiltersScores: false
});

The same query with sumOrFiltersScores = true returns a score of 6 (google (3) + amazon(2) + facebook(1)).

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index.search('', {
  filters: "(company:Google<score=3> OR company:Amazon<score=2> OR company:Facebook<score=1>)",
  sumOrFiltersScores: true
});

Scoring ANDs and ORs

Use the OR operator when you want to weigh terms differently.

• When filtering with OR, the overall score is based on the individual true value scores. If you have three filter values in your query and all three match, it will have a higher score than another record that matches only one filter value.
• Filtering only with ANDs removes the effect of scoring. With a group of ANDs, records are only chosen if all filters match: all records will have the same score.

Scoring using numeric filters

You can’t apply scores with numeric filters (like >=, !=, >). Scoring can only be done on facet values using the attribute:value<score=X> syntax.