[Book review] Relevant Search
- Relevant Search: With applications for Solr and Elasticsearch
- Doug Turnbull
- John Berryman
The search relevance problem
Given an increasingly large amount of information, it is infeasible for users to retrieve what they needed. Relevance scoring is therefore essential for search engines.
In general, the relevance engineers have to identify the most important features describing the content, the user, or the search query, transfer those features to the search engine, then measure what’s relevant to the search by crafting signals and finally balance the weights of the signals to rank the results.
Unfortunately, it is a challenging problem. Each search application serves a different type of content and thus has different expectation for relevance. Consequently, there is no silver bullet to solve this problem. Even the academic field that thoroughly study this problem, information retrieval is not a one-size-fit all solution. Relevance is strongly tied with the field and the application purpose.
Tackling the problem
The book approaches the problem first by a top-down analysis of how a typical search engine works. It then shows how a search query is processed by the search engine. After providing basic knowledge of how search work, the authors give some examples of relevance score tuning and show how it helps improving the relevance of the search results. Not stopping at the technical view, the authors also approach the problem from business view: they note that interdiscipline collaboration is important in order to define and increase relevance.
What I like
The book approaches the problem from various views: business view, algorithmic view, and practical view (giving examples). The book accentuates the diversity of problems and thereby encouraging readers to critically think of their own problems. While it suggests that search results should be influenced by sponsors, it also notes that without balance that will as well lead to failure.
What I don’t like
Its structure is somewhat unclear and flow to me. I think some chapters can be re-ordered so it’s more logical. Also, I find weighing sponsors’ priorities over customers’ unethical, but that is probably just a harsh truth in this society rather than the authors’ view.
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