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The purpose of this study is to carry out a systematic literature review for evidence-based assessment of the effectiveness of thesaurus in digital information retrieval systems. It also aimed to identify the evaluation methods, evaluation measures and data collection tools which may be used in evaluating digital information retrieval systems.

A systematic literature review (SLR) of 344 publications from LISA and 238 from Scopus has been carried out to identify the evaluation studies for analysis, and 15 evaluation studies have been analyzed.

This study presents evidences for the effectiveness of thesaurus in digital information retrieval systems. Various methods for evaluating digital information systems have been identified. Also, a wide range of evaluation measures and data collection tools have been identified.

The study was limited to the literature published in English language and indexed in LISA and Scopus. The evaluation methods, evaluation measures and data collection tools identified in this study may be used to design more cognizant evaluation studies for digital information retrieval systems.

The findings have significant implications for the administrators of any type of digital information retrieval systems in making more informed decisions toward implementation of thesaurus in resource description and access to digital collections.

This study extends our knowledge on the potentials of thesauri in digital information retrieval systems. It also provides cues for designing more cognizant evaluation studies for digital information systems.

The modern history of the information retrieval thesaurus may be dated from 1947. Even at this early stage a confusion of terminology and purpose was evident. The situation was only partly clarified by the emergence of the first fully operational information retrieval thesaurus in 1959. The intervening period produced a number of theoretical and practical contributions which shaped the thesaurus concept for operational use. The major ideas and influences of this period are examined and related.

This article provides an overview of recent developments relating to the application of thesauri in information organisation and retrieval on the World Wide Web. It describes some recent thesaurus projects undertaken to facilitate resource description and discovery and access to wide‐ranging information resources on the Internet. Types of thesauri available on the Web, thesauri integrated in databases and information retrieval systems, and multiple‐thesaurus systems for cross‐database searching are also discussed. Collective efforts and events in addressing the standardisation and novel applications of thesauri are briefly reviewed.

The paper aims to assess the utility of non‐agriculture‐specific information systems, databases, and respective controlled vocabularies (thesauri) in organising and retrieving agricultural information. The purpose is to identify thesaurus‐linked tree structures, controlled subject headings/terms (heading words, descriptors), and principal database‐dependent characteristics and assess how controlled terms improve retrieval results (recall) in relation to free‐text/uncontrolled terms in abstracts and document titles.

Several different hosts (interfaces, platforms, portals) and databases were used: CSA Illumina (ERIC, LISA), Ebscohost (Academic Search Complete, Medline, Political Science Complete), Ei‐Engineering Village (Compendex, Inspec), OVID (PsycINFO), ProQuest (ABI/Inform Global). The search‐terms agriculture and agricultural and truncated word‐stem agricultur‐ were employed. Permuted (rotated index) search fields were used to retrieve terms from thesauri. Subject‐heading search was assessed in relation to free‐text search, based on abstracts and document titles.

All thesauri contain agriculture‐based headings; however, associative, hierarchical and synonymous relationships show important inter‐database differences. Using subject headings along with abstracts and titles in search syntax (query) sometimes improves retrieval by up to 60 per cent. Retrieval depends on search fields and database‐specifics, such as autostemming (lemmatization), explode function, word‐indexing, or phrase‐indexing.

Inter‐database and host comparison, on consistent principles, can be limited because of some particular host‐ and database‐specifics.

End‐users may exploit databases more competently and thus achieve better retrieval results in searching for agriculture‐related information.

The function of as many as ten databases in different disciplines in providing information relevant to subject matter that is not a topical focus of databases is assessed.

There is a huge amount of information and data stored in publicly available online databases that consist of large text files accessed by Boolean search techniques. It is widely held that less use is made of these databases than could or should be the case, and that one reason for this is that potential users find it difficult to identify which databases to search, to use the various command languages of the hosts and to construct the Boolean search statements required. This reasoning has stimulated a considerable amount of exploration and development work on the construction of search interfaces, to aid the inexperienced user to gain effective access to these databases. The aim of our paper is to review aspects of the design of such interfaces: to indicate the requirements that must be met if maximum aid is to be offered to the inexperienced searcher; to spell out the knowledge that must be incorporated in an interface if such aid is to be given; to describe some of the solutions that have been implemented in experimental and operational interfaces; and to discuss some of the problems encountered. The paper closes with an extensive bibliography of references relevant to online search aids, going well beyond the items explicitly mentioned in the text. An index to software appears after the bibliography at the end of the paper.

A thesaurus may be viewed as a graph, and document retrieval algorithms can exploit this graph when both the documents and the query are represented by thesaurus terms. These retrieval algorithms measure the distance between the query and documents by using the path lengths in the graph. Previous work with such strategies has shown that the hierarchical relations in the thesaurus are useful but the non‐hierarchical relations are not. This paper shows that when the query explicitly mentions a particular non‐hierarchical relation, the retrieval algorithm benefits from the presence of such relations in the thesaurus. Our algorithms were applied to the Excerpta Medica bibliographic citation database whose citations are indexed with terms from the EMTREE thesaurus. We also created an enriched EMTREE by systematically adding non‐hierarchical relations from a medical knowledge base. Our algorithms used at one time EMTREE and, at another time, the enriched EMTREE in the course of ranking documents from Excerpta Medica against queries. When, and only when, the query specifically mentioned a particular non‐hierarchical relation type, did EMTREE enriched with that relation type lead to a ranking that better corresponded to an expert's ranking.

A recent Aslib Research Department Project which investigated problems relating to the construction of thesauri for indexing and retrieval ended with two publications, to be published shortly by Aslib. During the project, extensive use was made of the thesauri held in the Aslib Library, and information about them was tabulated. Information concerning openly available thesauri is displayed below.

This paper discusses a knowledge based information retrieval model with hierarchical thesaurus. The model computes the conceptual distance between a query and an object and both are indexed with weighted terms from a hierarchical thesaurus. The hierarchical thesaurus is represented by a hierarchical‐concept graph (HCG) in which nodes represent concepts and directed edges represent generalisation relationships. Rada et al. have developed a similar model. However, their model considered only a binary indexing scheme and revealed some counter‐intuitive results. Our proposed model extends theirs by allowing the index term and the edge of the HCG to be weighted. A new concept mapping method is devised to overcome Rada's counter‐intuitive results. In addition, a scheme for allowing Boolean operators in user queries is provided with a formula for computing conceptual distance from negated index terms. Experimental results have shown that our model simulates human performance more closely than Rada's model.

IThis review has been sponsored by the Office for Scientific and Technical Information and the end product of the complete research will be a thesaurus of management terms. Parallel research in the business management area and also supported by OSTI is being conducted by David Dews, Librarian of the Manchester Business School, and K. D. C. Vernon, Librarian of the London Graduate School of Business Studies. As Mr Vernon is at present engaged in the construction of a faceted classification scheme for management, this investigation has concentrated on the possibility of utilizing faceted techniques to construct such a thesaurus.

ARIES, PHILIPPE. Un lexique par phrases descriptives. Bulletin de l'A.I.D., vol. 5, no. 4, 1966, p. 99–101.