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Boolean Language and Database Structure

Boolean Language and Database Structure. Legal Research & Writing Spring 2005. Portions of this lecture are adapted from West’s Instructional Aids Series: Terms and Connectors Searching on Westlaw ®. The Agenda. Search Theory and Techniques Types of searching Boolean Keyword

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Boolean Language and Database Structure

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  1. Boolean Language and Database Structure Legal Research & Writing Spring 2005 Portions of this lecture are adapted from West’s Instructional Aids Series: Terms and Connectors Searching on Westlaw®

  2. The Agenda • Search Theory and Techniques • Types of searching • Boolean • Keyword • Methods of Searching • Database Types and Structures • Content • Organization • Provenance

  3. Computer Searching:What You Have Already Done • Searching the Web with a search engine like Infoseek, Google, etc. • Searching specialized databases while working on undergraduate or other post-graduate degrees, e.g. Academic Universe, First Search

  4. Databases • What is a Database? • A collection of digitized information organized in such a way that a computer program can quickly select desired pieces of data. • Databases are Made Up of “records” • Think: documents • Records/Documents are Made Up of “fields” • Fields contain the individual elements of information

  5. Types of Databases • Highly organized containing identical document types with a common structure and standard set of defined and marked fields • Variable, with many diverse types of documents, consisting of various structures, formats and few defined and consistent fields

  6. Terminology May Vary

  7. Search Techniques: The Process • Identify a Database likely to contain the information you need • Determine the exact contents of that database • Coverage, Scope • Type of Documents (Cases, Statutes, Text, etc.) • Structure of Records (Fields) • Accuracy (Provenance) • Currency

  8. Search Techniques: The Process • Determine the type of searching supported by that DB’s architecture • Will it support full Boolean search queries? • Is it designed for keyword searching? • Is it designed for concept-based/natural language searching?

  9. Search Techniques: The Process • Define your issues • Formulate a search query accordingly • Generate Synonyms, Use Thesaurus if available • Remember the fundamental concept, most DBs consist of words • The art of searching lies in understanding how your issue is likely to be expressed in the documents contained within the database

  10. The Searcher’s Quandry • Relevancy vs. Precision • You want to retrieve every relevant document • You want no irrelevant documents in your search results • With professional searching, you will err on the side of relevancy

  11. Boolean Searching • The tool of choice for professionals • Maximizes both relevance and precision • Based on mathematical “Set Theory” • In Westlaw is labeled: “Terms and Connectors”

  12. Boolean Searching:Logical Operators • Three Logical Operators • AND (Conjunctive) • OR (Disjunctive) • NOT (Exclusionary) • Based on the idea of a universe of elements

  13. Basic Connectors: AND • erisa and divorce AND narrows search and retrieves records containing all of the words it separates

  14. Basic Connectors: OR OR broadens searches and retrieves records containing any of the words it separates. • In Westlaw type OR, or leave a space between terms • In Lexis, you must type the OR between terms Farmer or “estate tax”

  15. Basic Connectors: NOT NOT Narrows searches and retrieves records that do not contain the term following it. • In Lexis, type AND NOT between terms • In Westlaw type BUT NOT, or leave % between terms Capital and not gains

  16. Boolean Searching:Combining Connectors • Complex searches use multiple connectors • (fraud or theft or breach) and erisa The shaded areas indicated by the arrows reflect your set of retrieved documents.

  17. Boolean Searching: Phrase Searching • Use quotation marks in most DBs for limit your search result set to those documents which contain the specific phrase • Example: “Puerto Rico”, “Underground Storage Tank” • Some DBs use ADJ as a connector to indicate words adjacent to each other in either order

  18. Phrase Searching • Quotation marks around a phrase or term of art, such as “limited liability,” are used only when the concept is invariably stated the same way each time it is used. • Consider whether the phrase could appear another way, such as “liability was limited”. • A safer search would be to require limited and liability to be within the same sentence or within a specified number or words of each other. • Westlaw: “limited liability”Lexis: limited liability

  19. Boolean Searching:Numerical Connectors • A type of proximity searching • Restricts search result set to those containing your terms within a certain number of words before/after or within each other • Order of terms is irrelevant • Example: host /10 guest • /n in Westlaw and Lexis • Some DBs use the term NEAR

  20. Boolean Searching:Grammatical Connectors • A type of proximity searching • Restricts search result set to those containing your terms within a certain grammatical unit, a sentence or paragraph • Order of terms is irrelevant • Example: • Intoxication /s guest • Intoxicated /p guest • /s in Westlaw, /s in Lexis

  21. Boolean Searching:Ordered Connectors Numeric & Grammatical • Ordered connectors require that the terms on the left of the connector precede the terms on the right within the specified relationship. • Westlaw: under-ground +4 tank • Lexis: under-ground or underground pre/4 tank • This query requires that underground precedes tank by no more than four words. Any word(s) can appear between storage and tank. • This connector is often used when a word must appear twice within the specified relationship. jones +5 jones could be used to find references to Jones v. Jones.

  22. Boolean Searching:Connectors Summary

  23. Boolean Searching:Common Wildcard Symbols • *Truncation. This expands a search term to include all forms of a root word, eg: patent* retrieves patent, patents, patentable, patented, etc. • ! Root Expander for finding alternative spellings. Use to indicate an unlimited number of characters after a root syllable, eg: host! retrieves host, hostess, hosted, hosting

  24. Boolean Searching:Common Wildcard Symbols • Single-character wildcard for finding alternative spellings. Sometimes represented by the ?, sometimes by the *. • Example: The ? represents a single character; two ?? represent two characters; three ??? represent three characters, and so on. Use within or at the end of a word, eg: wom?n finds woman as well as women, and carbon fib?? finds carbon fiber or carbon fibre.

  25. Boolean Searching: Automatic Enhancements • The singular form of a word (or number) automatically retrieves the plural and possessive forms of the word, including irregular forms. • Search term 415also retrieves 415.5 or 415(b). • The plural or possessive, however, will not retrieve the singular. • Woman retrieves women, woman’s and women’s; women or woman’s will not retrieve woman. • Use the singular form of a word unless you have a good reason not to.

  26. Boolean Searching: Hyphenated Words • On Lexis, a hyphen within a word is treated as a space. • Ex: post-conviction gets post-conviction and post conviction but not postconviction. • On Lexis, if you have any question whether a word is hyphenated or not, search for both versions: • post-conviction AND postconviction

  27. Boolean Searching: Hyphenated Words • On Westlaw, a hyphen does not function as a space. It functions as a command to the system to look for all three variants: • Ex: post-conviction gets post-conviction and post conviction and also postconviction. • On Westlaw, if you have any question whether a word might or might not be hyphenated, add the hyphen. It can’t hurt.

  28. Boolean Searching: Acronyms • Westlaw: Use periods between the letters of an acronym to retrieve all variations of the acronym. • periods between letters; • spaces between letters; • periods and spaces between the letters; • no period or spaces between letters. • E.P.A. retrieves E.P.A, E P A, E. P. A., and EPA. • Lexis: You would need to type out alternative forms of a term separated by the "or" connector • E.P.A. or E. P. A. or EPA or E P A

  29. Putting the Words Together • The first step is always identifying your issues and choosing words which express the concept • Always consider synonyms and word variants • Your search terms can then be combined with the connectors in a type of algebraic search string For this exercise let’s assume you want to retrieve all cases in a database that address: The liability of private party (a/k/a social) hosts for the acts of an intoxicated party guest

  30. Boolean Searching:Advanced Features • Order of Processing Issues • Change Default Search Order: Nesting Search Terms through the use of parenthesis • Think Junior High algebra equations • Date Restrictions • Segment Searching/Field Restrictors

  31. Order of Processing Connectors • “ “ • OR • Numerical Proximity Connectors (smallest to largest) • Grammatical Connectors (/s before /p) • AND • NOT E.g. host! /p intoxicat! ordr*nk! oralcohol! /s guest

  32. Changing the Default Order of Processing • Words within parentheses are processed first and then treated as a unit. • (defect! /s design!) or “product liability” retrieves either any extension of defect within the same sentence as any extension of design or “product liability”. • Parentheses are useful when you are searching for citations to multiple statutes: (42 +3 1981) (15 +3 311) will retrieve mention of 42 USC 1981 or 42 USCA 1981 or 15 USC 311 or 15 USCA 311.

  33. The Date Restriction Field • The date restriction (da) field is available in databases in which the documents are dated, such as case law, administrative decisions, and journals and law review databases. • You can require documents after a date, before a date, between two dates or on a specific date. • The added date (ad) field is used only to determine when documents were added to Westlaw.

  34. Fields/Segments • Remember: most documents in databases are divided into sections of text called fields (Westlaw) or segments (Lexis) • Field searching adds even more precision to a Boolean search. • The names and number of fields that a document contains depends on the type of database. A case law database has different fields than a statute law database. For example, there is no judge field in a statutory database.

  35. Fields on Westlaw • In Westlaw, most fields are entered in the search as a two-letter abbreviation. For example, the abbreviation for the title field in case law is “ti”. • In Lexis, full segment names are entered into the search. • The abbreviation of the field is immediately (no space) followed by parentheses. • A multi-term search within a field is constructed in the same way as a search that is not restricted to a specific field except that the terms are entered within the parentheses.

  36. Multiple Field Searching in Case Law • What if you only know that one party’s name is Smith, that Smith’s attorney’s name is Brown and that the case was decided after 1990? • ti(smith) AND at(brown) AND da(aft 1990) is the focused search that would retrieve the case (assuming you are in the correct database).

  37. Combining Unrestricted Searches and Field/Segment Searches • Many searches are a combination of unrestricted or free-text searches (words can be found anywhere in the document) and field searches. • “dying declaration” /p (time hour minute second day) /p (admiss! inadmissible admit!) & ju(jackson) • This search retrieves cases addressing a dying declaration and how long it can be asserted before death and be admissible according to Judge Jackson’s previous decisions.

  38. Other Types of Searching • Natural Language • Concept-Based • Keyword Searching

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