Define the query ratio as follows:
The query ratio is a normalized measure of how much faster a query runs with a join index than without a join index. For example, consulting the table about Creation and Elapsed Query Times for Different Join Indexes, you find a column of calculated query ratios.
Interpret these ratios as follows: Consider the query ratio for the creation cost of a single-table aggregate join index. The reported query value for this join index is 41. Therefore, the test query runs 41 times faster with the single-table aggregate join index defined than without it.