Searching for NZ Information in the Virtual Library Alastair G Smith School of Information Management Victoria University of Wellington

Overview Search engines: local vs global Search engines: limitations Searching for NZ info: effective strategies Information Quality on the Web Making NZ info more accessible: the role of librarians

NZ information online Online access can mean that US, European Information is easier to access than NZ E.g. Dialog However Internet provides accessible infrastructure for making NZ information available E.g. Knowledge Basket

Search tool definitions Directories: resources categorised by human beings: e.g. Yahoo! Te Puna Web Directory Search engines: automatically created databases of web pages, searchable by keyword e.g. Google, SearchNZ

Role of Search Engines Convenient, fast, usually find some information (if not most relevant) Most people turn to a search engine first (GVU user survey: 85%) For NZ Information we have a choice: Global search engines, e.g. Google Local search engines, e.g. SearchNZ

Comparing NZ and global search engines Experiment compared NZ, global and metasearch engines Test questions on NZ topics Compared relative recall

Global Search Engines AlltheWeb/FAST Google HotBot Altavista

Local Search Engines SearchNZ SearchNow (no longer exists) NZExplorer

Metasearch engines Excite Vivisimo Surfwax

Examples of test questions A description and image of the Maori flag Information about the Otago Central Rail Trail Information on the payment of British pensions in NZ

Recall Recall: proportion of possible relevant documents found in search, e.g. 100 relevant documents in database Search finds 20 relevant documents Recall is 20%

Problems in using recall to evaluate search engines: Don’t know total number of relevant documents on Web Ranking: Is document “found” if it appears in first 10, first 20…?

Relative Recall A B C Pool results of search engines A, B, C: approximates to all relevant documents

Recall in NZ search engine experiment “First 20 relative recall” Noted URLs of relevant documents found in first 20 hits for each search engine Pooled results for all search engines Used pooled list as approximation of all relevant documents

Recall results

Points arising from recall results Only one local search engine equalled global search engines No search engine found over half of relevant documents Metasearch engines did not outperform standalone search engines

Comparison with 2000

Factors affecting performance of NZ search engines Global search engines have similar or larger coverage of.nz sites NZ search engines have less sophisticated search features 36% of sites relevant to NZ topics were outside.nz domain Global search engines update more rapidly

Overlap of search engine hits

Implications of overlap results Most sites only found by one search engine Few sites found by 7 or more search engines Little overlap Comprehensive searches require several search engines

Why aren’t metasearch engines better? Metasearch engines select a few top ranked items from each search engine list Search engine ranking imperfect Looking at more results from one search engine may be as useful as looking at a few from each Metasearch engines use “lowest common denominator” search But can be useful for specific terminology

Limitations of Search Engines for finding NZ information “hidden web” How does a search engine work?…

Search engine architecture

Search engine limitations: Spider can’t access some types of pages: database, frames, javascript… Only 40% of pages are highly linked, others difficult for spider to locate Search is of database: “some of the pages that once existed on the Web” Spider may be optimised for popular sites rather than full coverage

Implications for Internet search strategy for NZ topics Use several search engines Avoid restricting search to.nz domain Don’t rely on search engines to find everything Use directories, subject resource guides Use as many words as possible to describe your topic: optimise relevance

NZ directory examples

NZ Subject Resource Guides

Searching in practice…

Quality of NZ information on the Web Like global information, and information in print: variable

NZ Information quality examples

Role of librarians in making NZ internet information available Sharing our knowledge of web navigation…

…Creating search tools and information resources

…Preserving Internet information

Conclusion NZ search engines do not offer advantages over global search engines Comprehensive searches involve several search engines, directories, subject guides Librarians have a role in creating local search tools, and in improving search skills