Query relaxation - a rewriting technique between search and recommendations

Rene Kriegler • Back to Haystack 2019

In search quality optimisation, various techniques are used to improve recall, especially in order to avoid empty search result sets. In most of the solutions, such as spelling correction and query expansion, the search query is modified while the original query intent is normally preserved.

In my talk, I shall describe my experiments with different approaches to query relaxation. Query relaxation is a query rewriting technique which removes one or more terms from multi-term queries that would otherwise lead to zero results. In many cases the removal of a query term entails a change of the query intent, making it difficult to judge the quality of the rewritten query and hence to decide which query term should be removed.

I argue that query relaxation might be best understood if it is seen as a technique on the border between search and recommendations. My focus is on a solution in the context of e-commerce search which is based on using Word2Vec embeddings and which finally made it into production.

Rene Kriegler


René has been working as a freelance search consultant for clients in Germany and abroad for more than ten years, often contracting for OpenSource Connections. Although he is interested in all aspects of search and NLP, key areas include search relevance consulting and e-commerce search. His technological focus is on Solr/Lucene. René co-organises MICES (Mix-Camp E-Commerce Search, Berlin, 19 June). He maintains the Querqy open source library.