Adding another post in their series about the 'inner workings' of Google, the Official Google Blog published an article earlier this week about the process of search evaluation - how they measure the quality of search results being produced and how they meet users' expectations.

As the post illustrates, there are many different factors that need to be taken into account and different approaches considered, but ultimately Google (and any other serious search engine) need to constantly review and revise the ways that search results are generated automatically and can meet the needs of the user as closely as possible, since that is the way that users will be retained as regular users.

There are 4 main stages of evaluating search results - understanding what a user's intent is when they search, comparing the quality of search results from different sources, assessing what is 'good' or most relevant, and finally considering different geographic locals and search options (particularly now that Google's universal search results combine answers from other sources, such as news, local search or video).

Google uses a team of human evaluators around the world to conduct search tests, as well as live traffic experiments to assess and review search quality. This can include statistical evaluation and a review of user actions, or a manual rating of the appropriateness, usefulness, and relevance of each individual related search suggestion. Clearly this can be a never-ending process that will never be perfect but at least tries to continually enhance the search experience for users as the knowledge and technology of search develops.