Medlars

UNIVERSITY OF MYSORE

MANASAGANGOTHRI

THIRD SEMESTER

Paper : Information RetrievalSeminar on :MEDLARS

Presented to,

Sunil, sir

Professor

Library and Information Science

Presented by,

Kumar, B

2nd year MLISC

Contents• Introduction

• MEDLARS

• Activities of MEDLARS

• Purpose of MEDLARS

• Prime requirements of MEDLARS

• Methodology

• Conclusion

• Reference

Introduction

• International information systems are organized to servethe needs of developed as well as developing countries onco-operative basis.

• These are established to store recorded information andretrieve it expeditiously.

• They provide free exchange of information amongscientists in various countries.

• The major International information systems &services are INIS, AGRIS, INSPEC, BIOSIS,MEDLARS, etc. •

• MEDLARS (Medical Literature Analysis & RetrievalSystem) is an online computer searching system & abibliographic service started by NLM, Maryland(USA)

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 tofurnish 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 thearticles from the world’s biomedical journals

Activities of MEDLARS

• Preparing of citations for the publication of Indexmedicus.

• Maintenance of several computer- readabledatabases including MEDLINE.

• Operation of online network.

• Provides SDILINE.

Purpose of Medlars

• To study the demand search requirements of MEDLARS users.

• To determine how effectively and efficiently the presentMEDLARS services are meeting its requirements.

• To determine factors adversely effecting the performance.

• To discover ways in which more effectively or more economicallyuser requirements can be satisfied

The prime requirements of demand search users were presumed to relate the following factors:

• The coverage of MEDLARS(i.e. the proportion of useful literatureon a particular topic, within the time limit imposed, i.e. indexedinto 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 relevantitems

• 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 toachieve a satisfactory response from the system.

The two most critical problems faced in the evaluation of medlars were:

•Ensuring that the body of test request was as far aspossible representative of the complete spectrum ofkinds of requests processed.

• Establishing methods for determining recall andprecision performance.

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)

METHODOLOGY• The user group so selected provided 302 search requests .Each

query was formulated in terms of Mesh by the system operatorand searches were conducted . After completion of a search thesample 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 markeach retrieved item using the following scale: H1-of Minorvalue; 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.

• Queries were submitted to the MEDLARS and on receiptof the queries; MEDLARS staff prepared a searchformulation (i.e. query designation) for each query usingan appropriate combination of Mesh terms. A computersearch was then carried out in the normal way. At thisstage each user was also asked to submit a list of recentarticles that he judged to be relevant to his query.

• The result of a search for recall and precision for all of the302 searches were brought together the average overallrecall ratio was found to be 57.7% and the precision ratio50.4% over the 302 searches , 797 recall failures and3038 precision failures were noted.

conclusion

The results of the MEDLARS test led to a series ofrecommendations for the improvement of the MEDLARS performance.Some notable changes made to the MEDLARS as a result of this testinclude design of a new search request form (intended to ensure that arequest statement is a good reflection of the information need behindit); and expansion of the entry vocabulary and improvement of itsaccessibility, and the adoption of an increased level of integrationamong personnel involved in indexing, searching and vocabularycontrol devices.

references

• http://www.slideshare.net/silambu111/evaluation-of-medlars

• http://www.slideshare.net/VISHNUMAYARS/medline-29060777