Search engines
From HLWIKI Canada
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IntroductionSee also Google scholar, Scirus and Open Search Tools on the Web Google, Bing and Yahoo are three of the top search engines in the digital age. As such, they are directly linked to the work of librarians and information specialists, and trends such as open access and web 2.0. Search engines are so popular because they offer a quick way to search across the web with ease. Search engines, however, can introduce problems for some types of information retrieval, especially subject-based searching. For example, health librarians point to poor recall, consistency and authority control with search engines although they are deemed acceptable enough for most queries as they facilitate quick access. Browsing and precision trendsIt was inevitable that searching would take on some of the features of Web 2.0. Many of the earliest algorithms were based on the popularity of wisdom of the crowds. Now, information needs in workplaces arise in the context of collaboration and participation. At one end, health teams write collaboratively and participate in trials where comprehensive (high recall) searches are needed (though they may tolerate low precision to begin). At the other end, medical students and nurses work together to retrieve a few good articles. These health professionals do not require high recall but high precision and algorithms coupled with other forms of recommended websites produce acceptable results. As the web scales in size, new requirements emerge. Customized social search - offered by Google health - is likely to become more important as a means of offering targeted searching among a group of sites. These websites will be recommended or compiled by other workers and collaborators or other experts. However, it must be said that with the rise of search tools and social search, there is a concomitant decline in the use of traditional databases. This may be due to the simple truth that high recall and precision in searching is not required for most queries. Health library users, for example, have different requirements for literature reviews and basic information. Precision tolerance of health professionals is directly related to recall. In the Internet age, the notion of complete recall as an indicator of success seems outdated and unrealistic. Exhaustive searching is not always needed. The idea of leading users to an acceptable number of papers has led some librarians to suggest proportional recall (or relative recall) where success is expressed as the number of relevant documents retrieved, over relevant documents required. A pharmacist may need five relevant documents, but her search retrieves only three. Proportional recall is therefore three-fifths, or 60%. This measure, while appealing, is artificial in that few health library users can specify what they really need before searching, let alone how many documents they will need.
Challenges faced by search engines
General search engines
Social search
Science search engines
Health specific search tools
References
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