Search (397 results, page 1 of 20)

  • × theme_ss:"Retrievalstudien"
  1. Brown, M.E.: By any other name : accounting for failure in the naming of subject categories (1995) 0.16 
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    Abstract
    Research shows that 65-80% of subject search terms fail to match the appropriate subject heading and one third to one half of subject searches result in no references being retrieved. Examines the subject search terms geberated by 82 school and college students in Princeton, NJ, evaluated the match between the named terms and the expected subject headings, proposes an explanation for match failures in relation to 3 invariant properties common to all search terms: concreteness, complexity, and syndeticity. Suggests that match failure is a consequence of developmental naming patterns and that these patterns can be overcome through the use of metacognitive naming skills
    Date
    2.11.1996 13:08:22
  2. Ribeiro, F.: Subject indexing and authority control in archives : the need for subject indexing in archives and for an indexing policy using controlled language (1996) 0.15 
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    Abstract
    Describes an experiment carried out in the City Archives of Oporto, Portugal to test the relative value for information retrieval of controling or not controlling vocabulary in subject indexing. A comparison was made of the results obtained by searching 2 databases covering the same archival documents, one of them without any control in the indexing language and the other with authority control. Results indicate that the database where authority control in subject indexing was used showed better performance and efficiency in information retrieval than the database which used an uncontrolled subject indexing language. A significant complementarity between the databases was found, the addition of the retrievals of one database to those of the other adding considerable advantage. Posits the possibility of creating an archival authority list suitable for use in groups with identical characteristics, such as local archives of judicial groups. Such a list should include broader terms, representing subject classes, which will be subdivided into narrower terms, according to the particular needs of each archives or archival groups
    Source
    Journal of the Society of Archivists. 17(1996) no.1, S.27-54
  3. Voorbij, H.: ¬Een goede titel behoeft geen trefwoord, of toch wel? : een vergelijkend oderzoek titelwoorden - trefwoorden (1997) 0.15 
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    Abstract
    A recent survey at the Royal Library in the Netherlands showed that subject headings are more efficient than title keywords for retrieval purposes. 475 Dutch publications were selected at random and assigned subject headings. The study showed that subject headings provided additional useful information in 56% of titles. Subsequent searching of the library's online catalogue showed that 88% of titles were retrieved via subject headings against 57% through title keywords. Further precision may be achieved with the help of indexing staff, but at considerable cost
    Footnote
    Übers. d. Titels: A good title has no need of subject headings, or does it?: a comparative study of title keywords against subject headings
  4. Schabas, A.H.: ¬A comparative evaluation of the retrieval effectiveness of titles, Library of Congress Subject Headings and PRECIS strings for computer searching of UK MARC data (1979) 0.12 
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    Imprint
    London : University of London
  5. McDonald, S.; Stevenson, R.J.: Navigation in hyperspace : an evaluation of the effects of navigational tools and subject matter expertise on browsing and information retrieval in hypertext (1998) 0.11 
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    Abstract
    Examines the effectiveness of a map and a textual contents list on the navigation performance of subjects with and without prior knowledge of the text topic in hypertext. Subjects used the document to answer 10 questions. the results showed that performance in the map condition was superior to that of the contents list condition, which in turn was superior to that of the hypertext only condition. Knowledgeable subjects performed better than non-knowledgeable subjects, except in the map condition where their performance was equivalent. the results show that non-knowledgeable users tend to rely more heavily on navigational aids than knowledgeable users, and that aids were used primarily during browsing and information retrieval in hypertext
  6. Drabenstott, K.M.; Vizine-Goetz, D.: Using subject headings for online retrieval : theory, practice and potential (1994) 0.10 
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    Abstract
    Using subject headings for Online Retrieval is an indispensable tool for online system desingners who are developing new systems or refining exicting ones. The book describes subject analysis and subject searching in online catalogs, including the limitations of retrieval, and demonstrates how such limitations can be overcome through system design and programming. The book describes the Library of Congress Subject headings system and system characteristics, shows how information is stored in machine readable files, and offers examples of and recommendations for successful methods. Tables are included to support these recommendations, and diagrams, graphs, and bar charts are used to provide results of data analyses.
  7. Byrne, J.R.: Relative effectiveness of titles, abstracts, and subject headings for machine retrieval from the COMPENDEX services (1975) 0.09 
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    Abstract
    We have investigated the relative merits of searching on titles, subject headings, abstracts, free-language terms, and combinations of these elements. The COMPENDEX data base was used for this study since it combined all of these data elements of interest. In general, the results obtained from the experiments indicate that, as expected, titles alone are not satisfactory for efficient retrieval. The combination of titles and abstracts came the closest to 100% retrieval, with searching of abstracts alone doing almost as well. Indexer input, although necessary for 100% retrieval in almost all cases, was found to be relatively unimportant
    Source
    Journal of the American Society for Information Science. 26(1975), S.223-229
  8. Chu, H.: Factors affecting relevance judgment : a report from TREC Legal track (2011) 0.09 
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    Abstract
    Purpose - This study intends to identify factors that affect relevance judgment of retrieved information as part of the 2007 TREC Legal track interactive task. Design/methodology/approach - Data were gathered and analyzed from the participants of the 2007 TREC Legal track interactive task using a questionnaire which includes not only a list of 80 relevance factors identified in prior research, but also a space for expressing their thoughts on relevance judgment in the process. Findings - This study finds that topicality remains a primary criterion, out of various options, for determining relevance, while specificity of the search request, task, or retrieved results also helps greatly in relevance judgment. Research limitations/implications - Relevance research should focus on the topicality and specificity of what is being evaluated as well as conducted in real environments. Practical implications - If multiple relevance factors are presented to assessors, the total number in a list should be below ten to take account of the limited processing capacity of human beings' short-term memory. Otherwise, the assessors might either completely ignore or inadequately consider some of the relevance factors when making judgment decisions. Originality/value - This study presents a method for reducing the artificiality of relevance research design, an apparent limitation in many related studies. Specifically, relevance judgment was made in this research as part of the 2007 TREC Legal track interactive task rather than a study devised for the sake of it. The assessors also served as searchers so that their searching experience would facilitate their subsequent relevance judgments.
    Date
    12. 7.2011 18:29:22
    Source
    Journal of documentation. 67(2011) no.2, S.264-278
  9. Tibbo, H.R.: ¬The epic struggle : subject retrieval from large bibliographic databases (1994) 0.08 
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    Abstract
    Discusses a retrieval study that focused on collection level archival records in the OCLC OLUC, made accessible through the EPIC online search system. Data were also collected from the local OPAC at North Carolina University at Chapel Hill (UNC-CH) in which UNC-CH produced OCLC records are loaded. The chief objective was to explore the retrieval environments in which a random sample of USMARC AMC records produced at UNC-CH were found: specifically to obtain a picture of the density of these databases in regard to each subject heading applied and, more generally, for each records. Key questions were: how many records would be retrieved for each subject heading attached to each of the records; and what was the nature of these subject headings vis a vis the numer of hits associated with them. Results show that large retrieval sets are a potential problem with national bibliographic utilities and that the local and national retrieval environments can vary greatly. The need for specifity in indexing is emphasized
  10. Hider, P.: ¬The search value added by professional indexing to a bibliographic database (2017) 0.08 
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    Abstract
    Gross et al. (2015) have demonstrated that about a quarter of hits would typically be lost to keyword searchers if contemporary academic library catalogs dropped their controlled subject headings. This paper reports on an analysis of the loss levels that would result if a bibliographic database, namely the Australian Education Index (AEI), were missing the subject descriptors and identifiers assigned by its professional indexers, employing the methodology developed by Gross and Taylor (2005), and later by Gross et al. (2015). The results indicate that AEI users would lose a similar proportion of hits per query to that experienced by library catalog users: on average, 27% of the resources found by a sample of keyword queries on the AEI database would not have been found without the subject indexing, based on the Australian Thesaurus of Education Descriptors (ATED). The paper also discusses the methodological limitations of these studies, pointing out that real-life users might still find some of the resources missed by a particular query through follow-up searches, while additional resources might also be found through iterative searching on the subject vocabulary. The paper goes on to describe a new research design, based on a before - and - after experiment, which addresses some of these limitations. It is argued that this alternative design will provide a more realistic picture of the value that professionally assigned subject indexing and controlled subject vocabularies can add to literature searching of a more scholarly and thorough kind.
  11. Schultz Jr., W.N.; Braddy, L.: ¬A librarian-centered study of perceptions of subject terms and controlled vocabulary (2017) 0.08 
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    Abstract
    Controlled vocabulary and subject headings in OPAC records have proven to be useful in improving search results. The authors used a survey to gather information about librarian opinions and professional use of controlled vocabulary. Data from a range of backgrounds and expertise were examined, including academic and public libraries, and technical services as well as public services professionals. Responses overall demonstrated positive opinions of the value of controlled vocabulary, including in reference interactions as well as during bibliographic instruction sessions. Results are also examined based upon factors such as age and type of librarian.
  12. Hider, P.: ¬The search value added by professional indexing to a bibliographic database (2018) 0.08 
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    Abstract
    Gross et al. (2015) have demonstrated that about a quarter of hits would typically be lost to keyword searchers if contemporary academic library catalogs dropped their controlled subject headings. This article reports on an investigation of the search value that subject descriptors and identifiers assigned by professional indexers add to a bibliographic database, namely the Australian Education Index (AEI). First, a similar methodology to that developed by Gross et al. (2015) was applied, with keyword searches representing a range of educational topics run on the AEI database with and without its subject indexing. The results indicated that AEI users would also lose, on average, about a quarter of hits per query. Second, an alternative research design was applied in which an experienced literature searcher was asked to find resources on a set of educational topics on an AEI database stripped of its subject indexing and then asked to search for additional resources on the same topics after the subject indexing had been reinserted. In this study, the proportion of additional resources that would have been lost had it not been for the subject indexing was again found to be about a quarter of the total resources found for each topic, on average.
  13. Voorbij, H.: Titelwoorden - trefwoorden : een vergelijkend onderzoek (1997) 0.07 
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    Footnote
    Übers. d. Titels: Title words - subject headings: a comparative research
  14. Vakkari, P.; Huuskonen, S.: Search effort degrades search output but improves task outcome (2012) 0.07 
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    Abstract
    We analyzed how effort in searching is associated with search output and task outcome. In a field study, we examined how students' search effort for an assigned learning task was associated with precision and relative recall, and how this was associated to the quality of learning outcome. The study subjects were 41 medical students writing essays for a class in medicine. Searching in Medline was part of their assignment. The data comprised students' search logs in Medline, their assessment of the usefulness of references retrieved, a questionnaire concerning the search process, and evaluation scores of the essays given by the teachers. Pearson correlation was calculated for answering the research questions. Finally, a path model for predicting task outcome was built. We found that effort in the search process degraded precision but improved task outcome. There were two major mechanisms reducing precision while enhancing task outcome. Effort in expanding Medical Subject Heading (MeSH) terms within search sessions and effort in assessing and exploring documents in the result list between the sessions degraded precision, but led to better task outcome. Thus, human effort compensated bad retrieval results on the way to good task outcome. Findings suggest that traditional effectiveness measures in information retrieval should be complemented with evaluation measures for search process and outcome.
    Source
    Journal of the American Society for Information Science and Technology. 63(2012) no.4, S.657-670
  15. McJunkin, M.C.: Precision and recall in title keyword searching (1995) 0.07 
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    Abstract
    Investigates the extent to which title keywords convey subject content and compares the relative effectiveness of searching title keywords using 2 search strategies to examine whether adjacency operators in title keyword searches are effective in improving recall and precision of online searching. Title keywords from a random sample of titles in the field of economics were searched on FirstSearch, using the WorldCat database, which is equivalent in coverage to the OCLC OLUC, with and without adjacency of the keywords specified. The LCSH of the items retrieved were compared with the sample title subject headings to determine the degree of match or relevance and the values for precision and recall were calculated. Results indicated that, when keywords were discipline specific, adjacency operators improved precision with little degradation of recall. Systems that allow positional operators or rank output by proximity of terms may increase search success
  16. Cleverdon, C.W.; Mills, J.: ¬The testing of index language devices (1985) 0.06 
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    Abstract
    A landmark event in the twentieth-century development of subject analysis theory was a retrieval experiment, begun in 1957, by Cyril Cleverdon, Librarian of the Cranfield Institute of Technology. For this work he received the Professional Award of the Special Libraries Association in 1962 and the Award of Merit of the American Society for Information Science in 1970. The objective of the experiment, called Cranfield I, was to test the ability of four indexing systems-UDC, Facet, Uniterm, and Alphabetic-Subject Headings-to retrieve material responsive to questions addressed to a collection of documents. The experiment was ambitious in scale, consisting of eighteen thousand documents and twelve hundred questions. Prior to Cranfield I, the question of what constitutes good indexing was approached subjectively and reference was made to assumptions in the form of principles that should be observed or user needs that should be met. Cranfield I was the first large-scale effort to use objective criteria for determining the parameters of good indexing. Its creative impetus was the definition of user satisfaction in terms of precision and recall. Out of the experiment emerged the definition of recall as the percentage of relevant documents retrieved and precision as the percentage of retrieved documents that were relevant. Operationalizing the concept of user satisfaction, that is, making it measurable, meant that it could be studied empirically and manipulated as a variable in mathematical equations. Much has been made of the fact that the experimental methodology of Cranfield I was seriously flawed. This is unfortunate as it tends to diminish Cleverdon's contribu tion, which was not methodological-such contributions can be left to benchmark researchers-but rather creative: the introduction of a new paradigm, one that proved to be eminently productive. The criticism leveled at the methodological shortcomings of Cranfield I underscored the need for more precise definitions of the variables involved in information retrieval. Particularly important was the need for a definition of the dependent variable index language. Like the definitions of precision and recall, that of index language provided a new way of looking at the indexing process. It was a re-visioning that stimulated research activity and led not only to a better understanding of indexing but also the design of better retrieval systems." Cranfield I was followed by Cranfield II. While Cranfield I was a wholesale comparison of four indexing "systems," Cranfield II aimed to single out various individual factors in index languages, called "indexing devices," and to measure how variations in these affected retrieval performance. The following selection represents the thinking at Cranfield midway between these two notable retrieval experiments.
    Source
    Theory of subject analysis: a sourcebook. Ed.: L.M. Chan, et al
  17. Bar-Ilan, J.: ¬The Web as an information source on informetrics? : A content analysis (2000) 0.06 
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    Abstract
    This article addresses the question of whether the Web can serve as an information source for research. Specifically, it analyzes by way of content analysis the Web pages retrieved by the major search engines on a particular date (June 7, 1998), as a result of the query 'informetrics OR informetric'. In 807 out of the 942 retrieved pages, the search terms were mentioned in the context of information science. Over 70% of the pages contained only indirect information on the topic, in the form of hypertext links and bibliographical references without annotation. The bibliographical references extracted from the Web pages were analyzed, and lists of most productive authors, most cited authors, works, and sources were compiled. The list of reference obtained from the Web was also compared to data retrieved from commercial databases. For most cases, the list of references extracted from the Web outperformed the commercial, bibliographic databases. The results of these comparisons indicate that valuable, freely available data is hidden in the Web waiting to be extracted from the millions of Web pages
    Source
    Journal of the American Society for Information Science. 51(2000) no.5, S.432-443
  18. Khan, K.; Locatis, C.: Searching through cyberspace : the effects of link display and link density on information retrieval from hypertext on the World Wide Web (1998) 0.06 
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    Abstract
    This study investigated information retrieval from hypertext on the WWW. Significant main and interaction effects were found for both link density (number of links per display) and display format (in paragraphs or lists) on search performance. Low link densities displayed in list format produced the best overall results, in terms of search accuracy, search time, number of links explored, and search task prioritization. Lower densities affected user ability to prioritize search tasks and produced more accurate searches, while list displays positively affected all aspects of searching except task prioritization. The performance of novices and experts, in terms of their previous experience browsing hypertext on the WWW, was compared. Experts performed better, mostly because of their superior task prioritization
    Source
    Journal of the American Society for Information Science. 49(1998) no.2, S.176-182
  19. Voorbij, H.: Title keywords and subject descriptors : a comparison of subject search entries of books in the humanities and social sciences (1998) 0.06 
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    Abstract
    In order to compare the value of subject descriptors and title keywords as entries to subject searches, two studies were carried out. Both studies concentrated on monographs in the humanities and social sciences, held by the online public access catalogue of the National Library of the Netherlands. In the first study, a comparison was made by subject librarians between the subject descriptors and the title keywords of 475 records. They could express their opinion on a scale from 1 (descriptor is exactly or almost the same as word in title) to 7 (descriptor does not appear in title at all). It was concluded that 37 per cent of the records are considerably enhanced by a subject descriptor, and 49 per cent slightly or considerably enhanced. In the second study, subject librarians performed subject searches using title keywords and subject descriptors on the same topic. The relative recall amounted to 48 per cent and 86 per cent respectively. Failure analysis revealed the reasons why so many records that were found by subject descriptors were not found by title keywords. First, although completely meaningless titles hardly ever appear, the title of a publication does not always offer sufficient clues for title keyword searching. In those cases, descriptors may enhance the record of a publication. A second and even more important task of subject descriptors is controlling the vocabulary. Many relevant titles cannot be retrieved by title keyword searching because of the wide diversity of ways of expressing a topic. Descriptors take away the burden of vocabulary control from the user.
    Source
    Journal of documentation. 54(1998) no.4, S.466-476
  20. Abdou, S.; Savoy, J.: Searching in Medline : query expansion and manual indexing evaluation (2008) 0.06 
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    Abstract
    Based on a relatively large subset representing one third of the Medline collection, this paper evaluates ten different IR models, including recent developments in both probabilistic and language models. We show that the best performing IR models is a probabilistic model developed within the Divergence from Randomness framework [Amati, G., & van Rijsbergen, C.J. (2002) Probabilistic models of information retrieval based on measuring the divergence from randomness. ACM-Transactions on Information Systems 20(4), 357-389], which result in 170% enhancements in mean average precision when compared to the classical tf idf vector-space model. This paper also reports on our impact evaluations on the retrieval effectiveness of manually assigned descriptors (MeSH or Medical Subject Headings), showing that by including these terms retrieval performance can improve from 2.4% to 13.5%, depending on the underling IR model. Finally, we design a new general blind-query expansion approach showing improved retrieval performances compared to those obtained using the Rocchio approach.

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