Search results

The characteristics of the experienced online searcher are identified and an attempt is made to show the ways in which the experienced searcher is able to enhance a basic search.

Many panel discussions and public presentations and miles of lines of print have been devoted in recent years to the question of what distinguishes a good online searcher from everyone else. Much of this verbiage appears somewhat self‐aggrandizing; searchers have been telling other searchers that it requires an extra special sort of person to do this job well. Online searching, it has been claimed, demands the very best people—intelligent, self‐confident, but also sympathetic and understanding, creative, and so on. Ordinary librarians cannot hope to excel at this complex and challenging task.

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.

When a term can be represented by an acronym, searches using both controlled terms and free text terms do not always retrieve all relevant items. It is necessary to add the acronym to the search strategy to ensure full coverage. Considerable differences exist between databases and searchers should evaluate the percentage of extra items that this technique will retrieve in the databases that they habitually use.

The major research objectives were to identify the differences among the searchers of users of online bibliographic systems who have different backgrounds of training and experience, and the differences among the searches of persons with and without experience of the Eric database. A quasi‐experimental research design used forty‐two searchers separated into five experience levels who conducted two pre‐selected searches using the Dialog system and the Eric database. The results were measured with variables which related to the search outcome, i.e., cost effectiveness, precision, and recall and to the search process and errors.

Term position information, as provided in some Boolean systems in the form of field restriction and term proximity, is reviewed and its value assessed. Non‐Boolean retrieval in the form of the ranked output experiment has not so far used term position information but has concentrated on schemes of term weighting. The use of term proximity devices is proposed here by analogy with Boolean techniques and seven algorithms are devised to incorporate the ideas of sentence matching, proximate terms, term order specification and term distance computations. It is hypothesised that term position will act as a precision device. A new search experiment is then described in which a test collection is processed into sentences and then output ranking using term position is obtained. Results are given for five algorithms compared against quorum searching as the benchmark. The best result increased the precision ratio by 18% and used proximate matching term pairs in sentences plus a distance component.

This paper reports experiments with a term weighting model incorporating relevance information in which it is assumed that index terms are distributed dependently. Initially this model was tested with complete relevance information against a similar model which assumes index terms are distributed independently. The experiments demonstrated conclusively that index terms are not independent for a number of diverse document collections. It was concluded that the use of relevance information together with dependence information could potentially improve retrieval effectiveness. As a result of further experiments the initial strict dependence model was modified and in particular a new relevance‐based term weight was developed. This modified dependence model was then used as the basis for relevance feedback, i.e. with partial relevance information only, and significant increases in retrieval effectiveness were achieved. The evaluation method used in the feedback experiments emphasized the effect of the feedback on documents which the potential user would not previously have seen. Finally the incorporation of relevance feedback in an operational system is considered and in particular it is argued that if high recall searches are required, relevance feedback based on the modified dependence model may be superior to the widely used Boolean search.

Online searchers in Australia were studied via a mailed questionnaire examining six sets of variables: backgrounds, experience, attitudes, behaviours, styles and satisfaction. They appeared to support preplanning, online interaction and relevance checks. In similar vein, they were mildly cost conscious and believed that their requesters were most satisfied with their performance. Those with greater experience tended to fit this description belter, as did those in special libraries.

Ranking of retrieved documents in the descending order of their association with the inquiry has been known in theory for a very long time, but so far it has found only limited use in operational online systems, Because of the ranking, the documents that are probably relevant are concentrated at the top of the set of documents retrieved and submitted for display. This affects the practical strategy of online retrieval that differs essentially from the search strategy in the traditional Boolean‐oriented systems: the inquirer does not need to reformulate his inquiry if it yields too many documents nor to be too anxious at the selection of inquiry terms. Consequently, types of inquiry can be used that are inadmissible in Boolean‐oriented systems or in systems that rank only a limited number of documents.

This section will present tips on Online searching, sample searches on various data bases, and search problems that our readers have found particularly challenging. We encourage reader participation, and accept contributions in any of the above areas. In addition, we are offering a prize of $50 for the best solution to the ‘Corner contest’ described below.