Basics of Information Retrieval and Query Formulation Bekele Negeri Duresa Nuclear Information Specialist

Outline  Information Retrieval  The INIS Collection  Planning searches  Formulating queries  Measure of Search effectiveness  Using search results and queries 2

Information Retrieval  Information Retrieval (IR) is finding material (usually documents) that satisfies an information need from within large collections (usually stored on computers).  Today we frequently think first of “web search”, but includes:  search  Searching your laptop  Corporate knowledge bases  Structured bibliographic databases 3

The INIS Collection  INIS Collection is comprised of  The INIS bibliographic Database (3,842,516 records)  The INIS Nonconventional Literature (NCL) collection (510,458 total and 369,140 publicly available)  A bibliographic database consists of data (records) whose attribute are described in fields and a means by which to search these fields, a search engine.  Databases may look different on screen but the underlying principles for searching and formulating search strategies are common to all. 4

Bibliographic Databases (Types)  Bibliographic Databases: provide only citation or reference author(s), title, subject(s) and publisher..) and with this information you should be able to locate the item in the Library.  Bibliographic with some full text content: these enhanced databases include keywords and abstracts and often, but not always, include the full text of a set of records.  Bibliographic databases with full text content: these databases include the entire full text for all articles and other documents indexed. 5

Planning your search  “Understanding the Problem is Half of the Solution”  Define precisely the information you are seeking  Identify the concepts that represent the problem 6

Planning a search: example Risk of medical radiation exposure?  To whom: to patients or doctors and medical technicians?  If to patients: are you concerned about exposure due to radiodiagnostics (CT, X-ray..) or due to radiation therapy or both?  If radiotherapy: are you concerned about radionuclide therapy or external irradiation therapy?  If about personnel: are you interested about safety policy of medical establishements? 7

Planning your search (Cont’d)  Topic: Risk of radiation exposure of medical staff in a radiotherapy department  Concepts:  Exposure to radiation  Medical staff  Radiotherapy  Are we looking for documents  In certain language, from certain country..  Latest publications  Only records with full text documents, or journal citations..? 8

IINIS Database Fields  Numerical (Exact or Range search)  Year of publication (PY)  Reference Number (RN)  Free Text  Title (TI) Authors (AU)  Source (SO)Abstract (AB)  Controlled Vocabulary  Language (LA)  Country of Input (CO)  Descriptors (DE)  Indexer-assigned descriptors (DEI)  Computer-upposted descriptors (DEC) 9

Search Strategy  Simple search  single search term or phrase  “Oncology”, “nuclear safety”  Advanced search (combining concepts)  Boolean Operators:OR, AND, NOT  Text Operators any (includes any), all (includes all), exact phrase  Numeric Operators equal, more, less, more or equal, less or equal  Truncation, Wildcard  Multilingual Search 10

Query Syntax Google Search Appliance 11

Query Formulation  Translating your search concepts into proper search syntax  For the Topic: Risk of radiation exposure of medical staff in a radiotherapy department  Simple to complex  MEDICAL PERSONNEL (is a BT for RADIOLOGICAL PERSONNEL)  OCCUPATIONAL EXPOSURE or OCCUPATIONAL SAFETY or RADIATION PROTECTION  RADIOTHERAPY  Try to search for individual terms and explore the database; you may identify other key concepts like radiation doses, ALARA, dose limits…  Then combine them using boolean operators (and, or, not)  Some databases allow you to combine searches while others allow you to combine your results during selection of records 12

Measuring Search Effectiveness  Precision & Recall  Recall: the ratio of the number of relevant records retrieved to the total number of relevant records in the database. 13

 Precision: the ratio of the number of relevant records retrieved to the total number of irrelevant and relevant records retrieved.  Precision and recall are Inversely related High recall = comprehensive retrieval but high noise High Precision = only relevant records but miss out good records Source: 14

Optimize your search strategy  Precision  Search in particular field  Search in DEI (indexer assigned descriptor)  Use exact Phrase  Combine using “AND”  Recall  Search across fields  Combine synonyms, related terms, broad or general terms  Use “any” or “all” words  Optimise  Use your best judgment  From simple to complex 15

Using your Query and search results  Selecting relevant records  select format (pdf/ html/excel..)  Printing/saving  search results  Storing query  Save and run query  Subscribe Feeds 16

Thank you! 17