Right now listing relevance is a very precise measure: a high listing relevance means a category page is a relevant result for the topic. In the SEA words, it will have a very high Quality Score (QS). However, a low listing relevance doesn't mean it has a poor QS, just that it might. Improve listing relevance recall without impacting precision, or at least impacting precision as little as possible.
This would allow us to use listing relevance to clean-up low relevance pages.
For instance, we might match singular and plural versions or match to other common n-grams for the topic or on the SERP.