Example 1: Using a small data set

This scenario shows the effects of various relevance ranking strategies on a small data set.

This example illustrates the richness of relevance ranking tuning possible with the modular relevance ranking system of the Oracle Endeca Server. Using two modules on a data set of three records, we found that all four possible combinations of the modules into strategies resulted in different orderings, all of which were different from the default ordering.

The example uses the following example record set:

Record	Title attribute	Author attribute
1	Great Short Stories	Mark Twain and other authors
2	Mark Twain	William Lyon Phelps
3	Tom Sawyer	Mark Twain

Creating the search interface

In a text editor, we have defined a search interface named Books, which contains both Title and Author standard attributes. The relevance rank is determined by the order in which the Endeca attributes appear in the members list.

Assume that we have not defined an explicit default sort order for the records, in which case their default order is determined by the system.

Without relevance ranking

Suppose that the user enters a record search query against the Books search interface for Mark Twain. Clearly all three of the records are hits, because each record has at least one searchable attribute value containing at least one occurrence of both the words Mark and Twain. But in what order should the results be presented to the user? Without relevance ranking enabled, the results will be returned in their default order: 1, 2, 3.

If relevance ranking were enabled, the order depends on the relevance ranking strategy selected.

With an Exact ranking strategy

Suppose we have selected the Exact relevance ranking strategy, either by assigning this as the default strategy for the Books search interface or by using query-level search options.

In this case, the order of results would be based only on whether results were Exact, Phrase, or other matches. Because records 2 and 3 have attributes whose complete values exactly match the user query Mark Twain, these results would be returned ahead of record 1, with the tie being broken by the default sort set by the system (remember that we have not defined a default sort).

With a Field ranking strategy

Now, assume that we have selected the Field relevance ranking strategy.

The order of results would be based only on which Endeca attribute caused the match, with Author matches being prioritized over Title matches. Because records 1 and 3 match on Author, these are returned ahead of record 2 (again, with ties broken by the default sort imposed by the system).

With a Field,Exact ranking strategy

Now, consider using a combination of these two strategies: Field,Exact.

In this case, the primary sort is determined by the first module, Field, which again dictates that records 1 and 3 should be returned ahead of record 2. But in this case, the Field tie between records 1 and 3 is resolved by the Exact module, which prioritizes record 3 ahead of record 1. Thus, the order of results returned is: 3, 1, 2.

With an Exact,Field ranking strategy

Finally, consider combining the same two modules but in a different priority order: Exact,Field.

In this case, the primary sort is determined by the Exact module, which again prioritizes records 2 and 3 ahead of record 1. In this case, the Exact tie between records 2 and 3 is resolved by the Field module, which orders record 3 ahead of record 2 because record 3 is an Author match. Thus, the order of results returned is: 3, 2, 1.