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Lewandowski, D.: Freiwillige Selbstkontrolle, Stärkung "alternativer Suchmaschinen" : Suchmaschinen und Politik (2005)
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Lewandowski, D.: Neue Suchmaschinen, neue Datenbestände, Desktop-Suche, Shortcuts (2005)
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Lewandowski, D.; Mayr, P.: Exploring the academic invisible Web (2006)
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- Abstract
- Purpose: To provide a critical review of Bergman's 2001 study on the Deep Web. In addition, we bring a new concept into the discussion, the Academic Invisible Web (AIW). We define the Academic Invisible Web as consisting of all databases and collections relevant to academia but not searchable by the general-purpose internet search engines. Indexing this part of the Invisible Web is central to scien-tific search engines. We provide an overview of approaches followed thus far. Design/methodology/approach: Discussion of measures and calculations, estima-tion based on informetric laws. Literature review on approaches for uncovering information from the Invisible Web. Findings: Bergman's size estimate of the Invisible Web is highly questionable. We demonstrate some major errors in the conceptual design of the Bergman paper. A new (raw) size estimate is given. Research limitations/implications: The precision of our estimate is limited due to a small sample size and lack of reliable data. Practical implications: We can show that no single library alone will be able to index the Academic Invisible Web. We suggest collaboration to accomplish this task. Originality/value: Provides library managers and those interested in developing academic search engines with data on the size and attributes of the Academic In-visible Web.
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Lewandowski, D.: Suchmaschinen (2013)
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Lewandowski, D.; Haustein, S.: What does the German-language information science community cite? (2015)
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Lewandowski, D.; Kerkmann, F.; Rümmele, S.; Sünkler, S.: ¬An empirical investigation on search engine ad disclosure (2018)
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- Abstract
- This representative study of German search engine users (N?=?1,000) focuses on the ability of users to distinguish between organic results and advertisements on Google results pages. We combine questions about Google's business with task-based studies in which users were asked to distinguish between ads and organic results in screenshots of results pages. We find that only a small percentage of users can reliably distinguish between ads and organic results, and that user knowledge of Google's business model is very limited. We conclude that ads are insufficiently labelled as such, and that many users may click on ads assuming that they are selecting organic results.
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Lewandowski, D.: ¬The retrieval effectiveness of web search engines : considering results descriptions (2008)
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- Abstract
- Purpose - The purpose of this paper is to compare five major web search engines (Google, Yahoo, MSN, Ask.com, and Seekport) for their retrieval effectiveness, taking into account not only the results, but also the results descriptions. Design/methodology/approach - The study uses real-life queries. Results are made anonymous and are randomized. Results are judged by the persons posing the original queries. Findings - The two major search engines, Google and Yahoo, perform best, and there are no significant differences between them. Google delivers significantly more relevant result descriptions than any other search engine. This could be one reason for users perceiving this engine as superior. Research limitations/implications - The study is based on a user model where the user takes into account a certain amount of results rather systematically. This may not be the case in real life. Practical implications - The paper implies that search engines should focus on relevant descriptions. Searchers are advised to use other search engines in addition to Google. Originality/value - This is the first major study comparing results and descriptions systematically and proposes new retrieval measures to take into account results descriptions.
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Lewandowski, D.; Sünkler, S.; Kerkmann, F.: Are ads on Google search engine results pages labeled clearly enough? : the influence of knowledge on search ads on users' selection behaviour (2017)
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- Abstract
- In an online experiment using a representative sample of the German online population (n = 1.000), we compare users' selection behaviour on two versions of the same Google search engine results page (SERP), one showing advertisements and organic results, the other showing organic results only. Selection behaviour is analyzed in relation to users' knowledge on Google's business model, on SERP design, and on these users' actual performance in marking advertisements on SERPs correctly. We find that users who were not able to mark ads correctly selected ads significantly more often. This leads to the conclusion that ads need to be labeled more clearly, and that there is a need for more information literacy in search engine users.
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Lewandowski, D.; Krewinkel, A.; Gleissner, M.; Osterode, D.; Tolg, B.; Holle, M.; Sünkler, S.: Entwicklung und Anwendung einer Software zur automatisierten Kontrolle des Lebensmittelmarktes im Internet mit informationswissenschaftlichen Methoden (2019)
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Lewandowski, D.: Informationsarmut : sowohl ein quantitatives als auch ein qualitatives Problem (1999)
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Lewandowski, D.: Wie können sich Bibliotheken gegenüber Wissenschaftssuchmaschinen positionieren? (2007)
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Lewandowski, D.: "Find what I mean not what I say" : Neuere Ansätze zur Qualifizierung von Suchmaschinen-Ergebnissen (2001)
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Lewandowski, D.: Aktualität als erfolgskritischer Faktor bei Suchmaschinen (2006)
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Lewandowski, D.: Was Google nicht kann, aber Yahoo (2004)
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Lewandowski, D.: Evaluierung von Suchmaschinen (2011)
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Lewandowski, D.: Wie "Next Generation Search Systems" die Suche auf eine neue Ebene heben und die Informationswelt verändern (2017)
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Lewandowski, D.: ¬The retrieval effectiveness of search engines on navigational queries (2011)
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- Abstract
- Purpose - The purpose of this paper is to test major web search engines on their performance on navigational queries, i.e. searches for homepages. Design/methodology/approach - In total, 100 user queries are posed to six search engines (Google, Yahoo!, MSN, Ask, Seekport, and Exalead). Users described the desired pages, and the results position of these was recorded. Measured success and mean reciprocal rank are calculated. Findings - The performance of the major search engines Google, Yahoo!, and MSN was found to be the best, with around 90 per cent of queries answered correctly. Ask and Exalead performed worse but received good scores as well. Research limitations/implications - All queries were in German, and the German-language interfaces of the search engines were used. Therefore, the results are only valid for German queries. Practical implications - When designing a search engine to compete with the major search engines, care should be taken on the performance on navigational queries. Users can be influenced easily in their quality ratings of search engines based on this performance. Originality/value - This study systematically compares the major search engines on navigational queries and compares the findings with studies on the retrieval effectiveness of the engines on informational queries.
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Lewandowski, D.: Suchmaschinen als Konkurrenten der Bibliothekskataloge : Wie Bibliotheken ihre Angebote durch Suchmaschinentechnologie attraktiver und durch Öffnung für die allgemeinen Suchmaschinen populärer machen können (2006)
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Lewandowski, D.: Nachweis deutschsprachiger bibliotheks- und informationswissenschaftlicher Aufsätze in Google Scholar (2007)
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Lewandowski, D.: Perspektiven eines Open Web Index (2016)
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