Medlars
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This document discusses the MEDLARS system, which is an online medical literature analysis and retrieval system started by the National Library of Medicine. It summarizes that MEDLARS began in 1960 and became operational in 1964 with the first computer-produced issue of Index Medicus. The document also notes that a study was conducted to evaluate MEDLARS by submitting 302 search requests from users and assessing recall and precision. The average recall was found to be 57.7% and precision was 50.4% based on the user relevance assessments. Recommendations were made to improve MEDLARS performance based on the results.
Medlars
- 1. UNIVERSITY OF MYSORE MANASAGANGOTHRI THIRD SEMESTER Paper : Information Retrieval Seminar on :MEDLARS Presented to, Sunil, sir Professor Library and Information Science Presented by, Kumar, B 2nd year MLISC
- 3. Contents • Introduction • MEDLARS • Activities of MEDLARS • Purpose of MEDLARS • Prime requirements of MEDLARS • Methodology • Conclusion • Reference
- 4. Introduction • International information systems are organized to serve the needs of developed as well as developing countries on co-operative basis. • These are established to store recorded information and retrieve it expeditiously. • They provide free exchange of information among scientists in various countries.
- 5. • The major International information systems & services are INIS, AGRIS, INSPEC, BIOSIS, MEDLARS, etc. • • MEDLARS (Medical Literature Analysis & Retrieval System) is an online computer searching system & a bibliographic service started by NLM, Maryland (USA)
- 6. Medlars • The work on MEDLARS began in 1960 & the system has several major revisions. • Came into operation in 1964. MEDLARS System MEDLARS is a computerized storage & retrieval system to furnish bibliographic access to NLM’s large biomedical collection. It became operational with the 1st computer produced issue of ‘Index Medicus’, a comprehensive subject- author index, to the articles from the world’s biomedical journals
- 7. Activities of MEDLARS • Preparing of citations for the publication of Index medicus. • Maintenance of several computer- readable databases including MEDLINE. • Operation of online network. • Provides SDILINE.
- 8. Purpose of Medlars • To study the demand search requirements of MEDLARS users. • To determine how effectively and efficiently the present MEDLARS services are meeting its requirements. • To determine factors adversely effecting the performance. • To discover ways in which more effectively or more economically user requirements can be satisfied
- 9. The prime requirements of demand search users were presumed to relate the following factors: • The coverage of MEDLARS(i.e. the proportion of useful literature on a particular topic, within the time limit imposed, i.e. indexed into the system) • Its recall power(i.e. its ability to retrieve relevant documents) • The precision power(i.e. the ability to hold back the non relevant items • The response time of the system • The format in which the search results are presented • The amount of effort the user must personally expend in order to achieve a satisfactory response from the system.
- 10. The two most critical problems faced in the evaluation of medlars were: •Ensuring that the body of test request was as far as possible representative of the complete spectrum of kinds of requests processed. • Establishing methods for determining recall and precision performance.
- 11. Computer- based products & services • AVLINE (Audio-Visual Online) • CANCERLIT (Cancer Literature) • CATLINE (Catalogue Online) • CHEMLINE (Chemical Dictionary Online) • TOXLINE (Toxicology information Online) • SDILINE (Selective Dissemination of Information Online) • SERLINE (Serials Online) • POPLINE (Population Information Online) • RTECS (Registry of Toxic effects of Chemical Substances Online ) • HISTLINE (History of Medicine Online) • MEDLINE (MEDLARS Online)
- 12. METHODOLOGY • The user group so selected provided 302 search requests .Each query was formulated in terms of Mesh by the system operator and searches were conducted . After completion of a search the sample output was sent to the users for relevance assessment. Photocopies of the articles, rather than the mere references, were supplied for the assessment. The user was asked to mark each retrieved item using the following scale: H1-of Minor value; W1-of no value; w2-Value unknown. • Precision of the searches was then calculated using the following formulas: • Precision ratio H1+H2 x100 L L is the number of sample items retrieved.
- 13. • Queries were submitted to the MEDLARS and on receipt of the queries; MEDLARS staff prepared a search formulation (i.e. query designation) for each query using an appropriate combination of Mesh terms. A computer search was then carried out in the normal way. At this stage each user was also asked to submit a list of recent articles that he judged to be relevant to his query. • The result of a search for recall and precision for all of the 302 searches were brought together the average overall recall ratio was found to be 57.7% and the precision ratio 50.4% over the 302 searches , 797 recall failures and 3038 precision failures were noted.
- 14. conclusion The results of the MEDLARS test led to a series of recommendations for the improvement of the MEDLARS performance. Some notable changes made to the MEDLARS as a result of this test include design of a new search request form (intended to ensure that a request statement is a good reflection of the information need behind it); and expansion of the entry vocabulary and improvement of its accessibility, and the adoption of an increased level of integration among personnel involved in indexing, searching and vocabulary control devices.