© Tefko Saracevic1 Types & structures of information resources What is out there for searching and what’s under the hood?

© Tefko Saracevic2 Definitions resource – Encarta Dictionary “Source of help …somebody who or something that can be used as a source of help or information … adeptness at finding solutions to problems” database – Webopedia.com “A collection of information organized in such a way that a computer program can quickly select desired pieces of data. You can think of a database as an electronic filing system.”

© Tefko Saracevic3 Definitions (cont.) Information databases are organized by fields, records, and files. A field is a single piece of information; a record is one complete set of fields; and a file is a collection of records. For example, a telephone book is analogous to a file. It contains a list of records, each of which consists of three fields: name, address, and telephone number.

© Tefko Saracevic4 Relations Terminology can be confusing & not consisted - so beware & do your own translation –Provider: a producer of databases; there are great many providers covering many fields e.g. Dept. of Education produces ERIC – abstracts & indexes educational materials (articles, reports) –Vendors or aggregators: organizations or companies that get databases from providers & organize them for searching; there are a number of vendors; some providers are their own vendors e.g DIALOG gets over 400 databases from a variety of providers, (among them ERIC) & then organizes them for searching

© Tefko Saracevic5 Example of a vendor: DIALOG acquires databases, from information providers at a fee organizes content according to given structures describes the content –done in Bluesheets, a most important search tool for you provides given searching capabilities –you have to master them for effective searching creates some own files – e.g super indexes provides you access at a fee –there is no such thing as free lunch

© Tefko Saracevic6 BTW – why DIALOG? Why do we use DIALOG for so many exercises? Several reasons –oldest and largest surviving vendor –most comprehensive set of databases –has a well developed instructional program –but most importantly: serves as a good test bed to develop searching skills that are generalizable –what you will systematically learn from using DIALOG can be translated to all searching & you get an insight into problems with searching

© Tefko Saracevic7 Other vendors/aggregators Good number of other vendors is around –the landscape is constantly changing –some available through RUL – examples (examine!) LexisNexis Factiva ScienceDirect EBSCOhost Ingenta … and on –some incorporate databases from producers, others create own databases from myriad of sources confusing?? wait, there is more…

© Tefko Saracevic8 Types of information databases Many types are available: –Bibliographic –Numeric –Full text –Directory –Image –Sound –Multimedia –Real time Some that are in DIALOG are also available elsewhere or on their own Some vendors have exclusive right to some databases Many you find in RUL

© Tefko Saracevic9 Examples of databases Over 200 available at RUL – examples that are relevant to library and information science Library and Information Science Abstracts Library Literature and Information Science Information Science and Technology Abstracts ERIC IEEE Xplore ACM Digital Library but others also cover materials of interest e.g –Web of Science –INSPEC

© Tefko Saracevic10 a BIG problem In DIALOG & some other vendors you can search a number of databases at the same time – so called federated searching –or in DIALOG search Dialindex – a meta index of databases BUT in RUL & elsewhere there is no federated searching –you have to search each database separately someday there will be federated searching, but at present do not hold your breath

© Tefko Saracevic11 as would imagine …

© Tefko Saracevic12 Now unto structures – getting under the hood Each database type has its own structure –why? to describe various parts of content for computers to recognize you can recognize that a section of a document is a title, but computer has to be told that a title is a title so that it can (among others) search for terms in a title when you request so Parts of documents (or objects in databases) are labeled as to as to content or function

© Tefko Saracevic13 Labeling schemes Many structure schemes were developed that prescribed what to label & what to call the label – meta languages –by providers, vendors, organizations, authorities –in different subjects, domains –for different types of objects Meta tags are used on the web – to describe & index –semantic web is in development, to further enable description of and searching for meaning MARC is a form of meta language To use these schemes for effective searching you have no choice but to get familiar

© Tefko Saracevic14 Transparency of structures In some databases description of structure is readily available –even though it may look forbidding, complicated good example: Bluesheets in DIALOG In others, structure is there but has to be discovered by surmising – even in But clever, appropriate use of structure in searching is key to effective searching …

© Tefko Saracevic15 Example: file 438 Bluesheet Library Literature and Information Science Describes the content of the file

© Tefko Saracevic16 file 438 fields - each is searchable SAMPLE RECORD [top] [top] Sample record: indicates structure

© Tefko Saracevic17 file 438: fields in Basic Index Basic index is searched by default – examples how to search fields in basic index

© Tefko Saracevic18 file 438: fields in Additional Indexes Additional index is searched by indicating the field to be searched – examples how to search them If you want to search the latest update only, add to search UD=9999 Neat trick:

© Tefko Saracevic19 file 438: fields in Limit Searches can be limited to cover documents with given attributes – examples how to limit searches

© Tefko Saracevic20 file 438: additional uses of structure Results can be sorted or ranked by given fields – examples how to sort or rank results

© Tefko Saracevic21 file 438: options in displaying of results Results can be displayed in a number of ways – examples of available formats But watch out! In real life some formats are free other cost $$$$!

© Tefko Saracevic22 Economics – tail that wags the whole dog In class DIALOG searching is free –& you can use it for class exercises, nothing else In real life DIALOG (as every other vendor) has an elaborate economic structure –different files have different price tags for use –time of use is calculated in DialUnits a Byzantine structure of charges beyond understanding –in different files different formats have different price attached some are rely hefty!

© Tefko Saracevic23 Where to find all about structure? In DIALOG in BlueSheets –consult often! and again! and again! and again! –files have similarities and differences in structure – BlueSheets show that For other vendors: –some have similar description as BlueSheets –some have to be dug up & surmised –in some revelation comes from checking what is available in advanced searching or in tips for searching

© Tefko Saracevic24 Structure in search engines Mostly not readily apparent –but all have capabilities to be used in searching Again: revelation comes from checking what is available in Advanced Search, Search Features, Search Tips, Help, & the like Most users do NOT take advantage of using available structures in searching –professional searchers do part of their tool kit & competencies

© Tefko Saracevic25 Example: structure from Advanced Search Records are structured at minimum by these fields

© Tefko Saracevic26 Another example: structure from Advanced Search Records are also structured at minimum by these fields

© Tefko Saracevic27 Similarities & differences All vendors & search engines have a basic search by default & an advanced search –but defaults & advanced capabilities differ & have to be confirmed for each –once you learn, you will apply variations on the theme

© Tefko Saracevic28 Similarities & differences … All vendors & search engines have basic & advanced Boolean- type search capabilities –but how it is done & bells and whistles differ –once you master concepts you can then do an AHA! when you encounter a variation & then translate

© Tefko Saracevic29 Similarities & differences … All vendors & search engines rank output results –but how it is done differs –DIALOG uses LIFO – Last in First Out as default, but also allows for other ways –search engines use ranking by relevance, clustering, PageRank … criteria not easy to discern

© Tefko Saracevic30 Similarities & differences … Most users –do not know or care about structure –do not search beyond default capabilities –do not look beyond one or two pages of results –miss many potentially relevant results –do not know what is under the hood Professional searchers –know that structure is very much connected to searching –learn about & use available structures –understand defaults & use advanced capabilities as necessary –know “tricks” for not missing stuff or not getting to much or to much junk –explore in order to learn what is under the hood

© Tefko Saracevic31 In conclusion! Searching is more art than science, but an art that needs a lot of knowledge what is behind it

© Tefko Saracevic32