Presentation on theme: "Measuring system performance. The library A system view Environment Transformational process InputsOutputs energy money materials personnel information."— Presentation transcript:
The library A system view Environment Transformational process InputsOutputs energy money materials personnel information products services UsersUsers
System performance measures recallprecision relevance
Robert Taylor's four levels of question formation The actual but unexpressed need for information (the visceral need) Q1 The conscious, within-brain description of the need (the conscious need) Q2 The formal statement of the need (the formalized need) Q3 The question as presented to the infor- mation system (the compromised need) Q4 Taylor, Robert S. 1968. Question-negotiation and information seeking in libraries. College & Research Libraries 29(3): 178-194 (May 1968).
System-defined relevance find health AND feet The health of the lumber 90% industry in terms of cubic feet of lumber produced "My feet are killing me."
Information retrieval process Question formulation Relevancy determination System: Which documents are relevant to the query? User: Are these documents relevant to my needs?
Defining relevance System-defined relevance User-defined relevance vs. Objective Often topical. Does it match the query? Subjective. Situational. Is it useful?
User-defined relevance The effect of lysergic acid diethylamide ingestion on toenail fungus in cloned mice "My feet are killing me." Soothing remedies for aching feet Controlling the body by controlling the mind-- meditative techniques for dealing with pain
Determining topical relevance Analyze work as to what it is about Assign to the document one or more terms from a finite list of topics Users can then search on those topic indicators
Recall Recall = No. of relevant documents retrieved Total no. of relevant documents in the file
Precision Precision = No. of relevant documents retrieved Total no. of documents retrieved from the file
Precision vs. Recall An inverse relationship As the level of recall rises the level of precision generally declines and vice versa. The Cranfield experiments (1957 & 1962) Cyril Cleverdon, p.i.
Precision vs. Recall Subject: sexual dimorphism Word stemming: sexsexessexual sexysexiersexiest Field-specific searches: DE,TI/sexual()dimorphism RecallPrecision RecallPrecision
User-defined relevance "Relevance appears to be a subjective quality, unique between the individual and a given document supporting the assumption that relevance can only be judged by the information user." Miranda Pao
Years later The effect of lysergic acid diethylamide ingestion on toenail fungus in cloned mice "My feet are still killing me." Soothing remedies for aching feet Controlling the body by controlling the mind-- meditative techniques for dealing with pain
Factors affecting relevance (1) Purpose of the information Situation of the user Level at which the information source is written –Journal of the Amer. Med. Assn. –Healthy times
Factors affecting relevance (2) Subject knowledge of the user –Is the data new to the user? –Does the information relate to the user's prior knowledge? Values - ethical, social, philosophical, political, religious, legal
User-defined relevance Subjectivity and fluidity make it difficult to use as measuring tool for system performance
Incorporating user-defined relevance into information retrieval systems (1) User performs search System retrieves results...
Incorporating user-defined relevance into information retrieval systems (2) System asks user if he/she would like to retrieve similar documents Search for other documents with similar word frequencies Search for other documents with same subject descriptors
Search for other documents with same subject descriptors Main Author: Title: Subject(s): Gribbin, John R. In search of Schrodinger's cat : quantum physics and reality / by John Gribbin. Schrodinger, Erwin, 1887-1961. Quantum theory History. Reality.
Assisting users in determining relevancy Indexing terms Title Citation data Abstract Source: Barry, Carol L. 1998. Document representations and clues to document relevance. Journal of the American Society for Information Science 49(14):1293-1303.
Document representation research Titles Full text Title: Getting good grades in graduate school Title: How to impress your advisor in graduate school Title: Writing a dissertation Title: The well-written graduate paper Getting good grades in graduate school The best way to get good grades is to study hard… How to impress your advisor in graduate school Never show up late for a meeting with your advisor… Writing a dissertation The first thing to do is to pick a topic that truly interests you… The well-written graduate paper Before finalizing your topic do a preliminary search on… How relevant are these?
Document representation research Titles Citation data Indexing terms Abstracts Full text Full text Full text Full text How relevant are these?
Utility studies - Indications that user found relevant materials Citation & abstract databases –User requests citations be formatted for printing –User requests citations be sent by e-mail –User downloads citations Full-text databases –Pull up the full text –Print the article –Download the article to their Blackberry
Utility studies - Indications that user found relevant materials Search Short list If user stops may not have found a relevant article chocolate
Utility studies - Indications that user found relevant materials Search Short list Modifies search View full citation data for article View full text of article Download or print article Assume that user found article relevant
Characteristics of searches that produce relevant materials Subject searching Utilization of Boolean operators Search modification Increased time in display activities User of greater number of databases Cooper, Michael Dr. and Hui-Min Chen. 2001. Predicting the relevance of a library catalog search. Journal of the American Society for Information Science and Technology 52 (10):813-827.
Importance of abstract (1) Indication as to depth/scope of the article Delineates methodology-- indication of reliability and validity Gives indication as to content novelty Authors studied leg-hair count variations of Drosophila in Kawainui Marsh Random sampling in 40 sectors during March, June, September & December Greater variation in June
Importance of abstract (2) Basis for research may indicate recency Delineation of results indicates "tangibility" (important, useful data) American housing market was selected because it is always robust. Authors concluded that American teenagers listen to rock music.
Types of abstracts Indicative Informative Critical (evaluative) (Not common in library databases)
Indicative abstract Indicates what the document is about but doesn't report findings Title: A review of the current literature on relevance. Abstract: The author reviews the current literature on relevance.
Informative abstract Acts as a substitute for the document Title: The effects of library school on the mental health of library students Abstract: The authors performed longitudinal studies on 32 graduate students in 8 library and information science programs and found a significant increase in aberrant psychological traits over time. (fictitious title and abstracts)
1.Word counts 2.Remove stop words 3.Weight remaining words according to frequency 4.Search for sentences with highest density of most frequently-occurring words
1. Word count Title: Seasonal variations in the feral cat population of Fargo the81 is68 a56 to42 cats61 number45 season27 winter11 summer11 spring11 fall11 monthly10 temperature61 variation12 food10 availability10 average9 concept7 per8 over9 immediate5 implement3 mortality8 survival9
2. Eliminate stop words Title: Seasonal variations in the feral cat population of Fargo the81 is68 a56 to42 cats61 number45 season27 winter11 summer11 spring11 fall11 monthly10 temperature61 variation12 food10 availability10 average9 concept7 per8 over9 immediate5 implement3 mortality8 survival9
3. Rank by frequency Title: Seasonal variations in the feral cat population of Fargo cats61 temperature61 number45 seasonal27 variation12 winter11 summer11 spring11 fall11 monthly10 food10 availability10 average9 survival9 mortality8 concept7 immediate5 implement3
4. Search for sentences with highest density of high frequency words Title: Seasonal variations in the feral cat population of Fargo We found a significant seasonal variation in the number of cats. The highest number of cats are found in the summer, the lowest number of cats in the winter.
Automated abstract... The Children's Internet Protection Act (CIPA) sets conditions on public libraries' receipt of federal financial assistance for Internet access.... It would not have been possible for the broadcasting station to limit the use of federal funds to all non-editorializing activities.... The instant Court distinguished Velazquez, restricting its holding to situations in which the grantee is "pit[ted]... against the Government.... " Justice Stevens asserted that the filtering condition was unconstitutional because it distorted the normal usage of library Internet terminals as sources of a wide array of information.... A condition mandating Internet filters distorts this mission by "deny[ing] patrons access to constitutionally protected speech that libraries would otherwise provide....
Relevance and information overload In this age of information overload, tools to aid the user in determining relevance are increasingly critical.