Searching Skills GuideBoolean, Truncation and Wildcards

Presented by: National Police LibraryDate: June 2013

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Why You Need This Guide• This searching guide is for people who would like to achieve better results when searching library catalogues and academic databases.

• Why might you need this guide?

• You are struggling to find articles and resources on a topic you are interested in.

• You want to ascertain whether any academic research on your topic even exists!

• You are overwhelmed by the amount of literature out there and want to reduce the number of results you are getting but…

• …you want to make sure the results you do get back are relevant and of high quality.

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• Most, if not all, library catalogues and subscription academic databases will enable the use of Boolean logic for searching. • Boolean (named for its inventor George Boole, a 19th century logician and mathematician) is a system which enables researchers to specify to a database which keywords they want found, and what relationship these words should have to each other. For example:

• Words like RESEARCH, STUDY and INVESTIGATE can all mean the same thing. You want to find at least one but not necessarily all of these words.

• You want to find literature on RAPE but not OILSEED RAPE.

The Basics The purpose of Boolean logic

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• Boolean is a powerful tool and can be used to create quite complex searches. The standard Boolean operators are:

ANDORNOT (or AND NOT)

• Boolean is most effective when used in combination with parentheses (round brackets), truncation and wildcards. These will all be explained in this guide.

Boolean operators

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• From the very simple:

crime AND punishmentgood NOT evil

murder OR homicide

• To the very complicated:

Example search strings

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OperatorsBoolean ‘AND’• When using AND in a simple search, the results retrieved will contain both search terms. In the diagram the documents retrieved by using this search expression are contained within the green area.

EXAMPLE: violence AND crime This will retrieve all records containing both of the words violence and crime.

VIOLENCE

CRIME

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Boolean ‘OR’

• OR is used to retrieve results that contain either search term as well as to retrieve results that contain both search terms. In the diagram the documents retrieved by using this search expression are contained within all the colour areas.

EXAMPLE: violence OR murder This will retrieve all records containing the words violence or murder, as well as those containing both.

MURDER

VIOLENCE

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Boolean ‘NOT’

• When using NOT (or AND NOT) in a simple search, the results retrieved will contain only the term used before the NOT. In the diagram the documents retrieved by using this search expression are contained within the light blue area.

EXAMPLE: crime NOT murder This will retrieve all records containing the word crime but not the word murder.

MURDERCRIME

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Use of ‘NOT’

• The NOT operator can hinder your search if used without care. While it is fairly certain that a search for:

rape NOT oilseed

…would not inadvertently exclude results relevant to you, the same cannot be said for:

murder NOT accident

• While seemingly distinctive topics, this search would exclude ‘Murder is no Accident’ from the results.

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2. Write Boolean operators between words in a search box.

*The library catalogue Heritage is a product of IS Oxford Ltd. The National Police Library online catalogue can be found at http://library.college.police.uk/default.htm

In the CatalogueSimple Boolean searches

1. Use the ‘drop down’ to combine search terms.

• You can use Boolean to perform simple searches in the National Police Library Catalogue* in two ways. From the advanced search screen you can:

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Layered Boolean searches

• With only what we’ve learned so far, we can also create slightly more complicated searches:

• In the search shown above the documents retrieved would contain the word murder, either or both of the words police or policing, and would not contain the word serial.

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• In simple searches, Heritage and many other search engines will process search terms from left to right.

• This helps the system recognise phrases and titles, therefore producing more relevant results*.

• However, as in maths, there is an Order of Operations for using Boolean operators.

• AND will be processed before OR.• AND NOT will be processed before AND.

Search LogicOrder of Operations 1

*For information on exact phrase and title searching using quotation marks, see slide 21.

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Order of Operations 2

• Consequently the way in which a search is constructed can have big implications for the search results. Lets say we want to find results related to corruption in the police.

Search for…

… and you will get

• Because the search combines policing and corruption, and then retrieves all catalogue entries containing the word police as well!

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• The simplest way to get the results you require is to group synonyms (or terms that belong together) using round brackets. Anything enclosed in brackets will then be worked out first.

• Using the example from the previous slide, we can see that using brackets ensures we get the correct search results.

Search for…

… and you will get

Adding StructureParentheses or round brackets

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• Making good use of the advanced search functions can also help reduce search errors. This is because the search boxes provide structure for the system to follow.

• All three searches above will produce the same results in the library catalogue.

• Advanced search functions can be combined with the use of brackets for very complex searches.

Advanced search

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Inclusive SearchingWord form variants• We are used to search engines which will try to interpret what we ‘meant’ to search for. However most databases and catalogues require precise spelling and word form use.

• In searching therefore, it is important to account for all applicable word forms.

• One way to do this would be to literally search for all tenses and forms of a word or phrase:

• Police: police OR policing OR policed... • Rape: rape OR raping OR rapist OR raped…• Sex offender: sex offender OR sex offence OR sexual

offence OR sexual offending OR…

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Truncation

• The easiest way to account for all variant word endings is to use to technique known as truncation. • Truncation is used by databases in order to expand a search to include all word endings and minimise the need to enter (or remember!) multiple word forms. The stem of the word is entered into the search box followed by the truncation symbol, often *.

• Politic* retrieves political, politics, politically.

• This technique cannot be used with all words though.

• Polic* retrieve police, policing, but also policy

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Wildcards

• You can account for alternative spellings of a word by using wildcards. Wildcard characters are used to replace a single letter in a word, like the blank tile in Scrabble. A commonly used wildcard symbol is ?.

• Organi?ation retrieves organisation, organization.• Breathaly?e retrieves breathalyse, breathalyze.

• Many databases will also use multi-character wildcards. These can be used to replace 1, multiple or 0 characters within a word, depending on the database. Symbols used include #* and $.

• H#emorrhage retrieves Haemorrhage, Hemorrhage.

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Combining symbols and database variation

• Most library databases use truncation and wildcards, and the two can be combined if required. It is advisable to do this with caution however, especially when using multi-character wildcards.

• Colo#r* retrieves Colour, Color, Colouring,but also might retrieve Collateral, Collars etc.

• When using truncation and wildcards it is important to be clear on what symbols a database uses and what rules apply to their usage.

• The table on the next slide shows the different symbols used by some of the main databases that the National Police Library provides access to.

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Database specific symbols

Database Truncation symbol

Wildcard symbol

Multi-Character Wildcard symbol(s) and usage notes

Heritage * ? * Finds any number of unknown characters

EBSCO * ? * Finds any number of unknown characters# Finds 0 or 1 unknown characters

ProQuest * ? * Finds up to 10 unknown characters[*n] Finds up to N unknown characters

Westlaw ! * Not available

Emerald * ? * Finds any number of unknown characters

Web of Knowledge

* ? * Finds any number of unknown characters$ Finds 0 or 1 unknown characters

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Other Tips…Double quote marks

• To search for an exact phrase, for example Police and Crime Commissoners use double quote marks “”. In most databases (including Heritage) you can use this function in conjunction with truncation or wildcards.

• Double quote marks can also be used where Boolean operators appear in a title to override the systems desire to AND, OR or NOT.

• “Police and crime commissioner*” • “Naked and Not Ashamed” (genuine book title)

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• Keywords or subject terms used by databases can be useful for creating a specific search, but should be used with caution as they vary wildly across, and even within databases.

• A general search for cyber-crime finds a variety of keywords across databases:

• If you wish to make use of a database’s keywords or subject terms it is recommended that you investigate the terms used in each database thoroughly.

Keywords and subject terms

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Proximity operators

• In addition to Boolean, wildcards and truncation, many databases include additional proximity operators to help you with your search. The most common are:

• NEAR – used to define how close together you would like terms to appear in a search.

• WITHIN – used to define how close together you would like terms to appear and in what order

EXAMPLES:In the table Shown, #represents a number

Database NEAR WITHIN

EBSCO N# W#

ProQuest NEAR/# PRE/#

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Using Search Engines

• Search engines tend to have their own search functions which are loosely based on Boolean principles. However, as they provide access to such vast reams of information, searching them successfully can prove tricky.

• While this guide is not designed to assist with using search engines, some tips on searching Google are included here to help you make the most of this resource:

• The minus symbol ‘-’ is used for NOT.• The plus symbol '+' can be used for AND, although Google

will AND words by default• Double quotes “” are used for phrase searching.• For more information, read Get more out of Google

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Contact Details National Police Library• For further information, or assistance with searching and information retrieval, please contact the National Police Library at:

• National Police LibraryCollege of PolicingAlbert Day BuildingSunningdale ParkLarch AvenueAscotBerkshireSL5 0QE

• T 01256 602650• E library@college.pnn.police.uk

All rights reserved, no part of this publication may be reproduced, modified, amended, stored in an retrieval system or transmitted, in any form or by any means, without the prior written permission of the National Police Library.

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References • ADAM Consortium. Boolean searching. ADAM Consortium: Surrey. [Accessed 24 April 2013] http://adam.ac.uk/info/boolean.html• CATONE, J., 2011. How to Use Google Search More Effectively [INFOGRAPHIC]. Mashable. [Accessed 24 June 2013] http://mashable.com/2011/11/24/google-search-infographic/• EBSCO, 2013. EBSCO help: basic search. EBSCO. [Accessed 24 April 2012] http://support.ebsco.com/help/index.php?help_id=50 • Emerald, 2013. Detailed “advanced search” functionality. Emerald Group. [Accessed 10 May 2013] http://www.emeraldinsight.com/help/user/advanced_functionality.htm • IS Oxford, 2013. Heritage: library management software. IS Oxford: Oxford. [Accessed 11 July 2012] http://www.isoxford.com/ • JAKES, T.D., 2005. Naked and not ashamed. Destiny Image: Shippensburg, PA.• Proquest, 2013. ProQuest help: basic search. Proquest LLC. [Accessed 24 April 2013] http://search.proquest.com/help/academic/webframe.html?Basic_Search.html • PROTHROW-STITH, Deborah; SPIVAK, Howard R., 2004. Murder is no accident: understanding and preventing youth violence in America. San Francisco: Jossey-Bass.• University Libraries, 2010. Using AND, OR, and NOT (Boolean Operators). University of Nevada: Reno. [Accessed 11 July 2012] http://knowledgecenter.unr.edu/help/using/booltips.aspx#parenthess • User Education Services, 2012. Using Boolean Logic or Connectors. University of Maryland Libraries: Maryland. [Accessed 10 May 2013] http://www.lib.umd.edu/ues/guides/boolean-logic• Westlaw, 2013. Westlaw UK Help - Terms and connectors used on Westlaw UK. Thomson Reuter. [Accesses 23 April 2013] http://login.westlaw.co.uk/