SummaryThe purpose of this paper is to describe various quality measures for search engines and to ask whether these are suitable. We especially focus on user needs and their use of Web search engines. The paper presents an extensive literature review and a first quality measurement model, as well. Findings include that Web search engine quality can not be measured by just retrieval effectiveness (the quality of the results), but should also consider index quality, the quality of the search features and Web search engine usability . For each of these sections, empirical results from studies conducted in the past, as well as from our own research are presented. These results have implications for the evaluation of Web search engines and for the development of better search systems that give the user the best possible search experience.
IntroductionWeb search engines have become important for information seeking in many different contexts (e.g., personal, business, and scientific). Research questions not answered satisfactorily are, as of now, how well these engines perform regarding user expectations and what measures should be used to get an overall picture of search engine quality . It is well known that search engine quality in its entirety cannot be measured with the use of traditional retrieval measures. But the development of new, search engine specific measures, as proposed in Vaughan (2004) are not sufficient, either. Search engine quality must be defined more extensively and integrate factors beyond retrieval performance such as index quality and the quality of the search features.One aspect neglected is the user himself. But to discuss and judge the quality of search engines, it is important to focus on the user of such systems, too. Better performance of ranking algorithms or providing additional services does not always lead to users' satisfaction and to better search results. We focus on the Web search engine user behaviour to derive strategies to measure Web search engine quality . Additionally, quality assurance is an important aspect to improve customer satisfaction and loyalty. This is fundamental to protect market shares and revenues from