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Search techniques

Does your search result in too many or too few hits? By using a set of different search techniques you will improve your searches considerably. What is described below are some basic techniques that will work in most databases.

The logic behind database searches

Searching in a database is matching your search words with existing words in the database. You enter one or several search words and the database will tell you whether these words can be found in the database or not. Most search tools automatically imply AND between each word entered. If you enter two words you will only get the results that include both words together in the same document.

There are search services that automatically search for related terms and synonyms. That kind of searches will yield a greater amount of hits.

Illustration of matching using two terms

What happens when you execute the search in the example is that you ask the database to return documents where the words politics AND democracy are included - no other documents. Had the search been executed using only the word politics, the upper left document had been returned by the database too.

In many databases you can also use OR between the search words. Applying this to the example below, we would obtain documents that either include bribes OR corruption. The operator OR is used when you want to increase the number of hits, and it is very useful if you want to search for all kinds of synonyms.

Illustration of search with the OR operator

Include different word endings with truncation

Besides choosing which words to search for, you also have to think about in which form you write them. If you, for instance, want to find publications about democratisation studies, you might also be interested in publications wherein such words as democratization with American English spelling, or any ending of the word, like democracies (plural form), or democratic (as in democratic parties) occur. Instead of doing several separate searches, you can use a so-called truncation. Enter the stem of the word and a truncation character, often an asterisk, like democra*, and you will retrieve all publications wherein the truncated word stem occurs, irrespective of which ending it has.   

Illustration of search with truncation.

In many databases the truncation character can also be used at the beginning or in the middle of a word. When it is used in the middle of the word it is usually called a wildcard.

The most common truncation character is the asterisk (*), but other characters might occur, such as the question mark (?). Sometimes, different characters are used depending on whether it is used inside or at the ending of the word. Read the search help text of the database you are currently searching in.

It might be good to know that Google uses a form of automatic truncation. A search might retrieve hits on other variants of the word used in your search. However, in the library's article databases, for instance, you usually have to truncate words in order to retrieve all variants.

Phrase search

By putting two or more words withing quotation marks, you will only retrieve documents wherein those words are in exactly that order. This technique works in most databases and search engines. Example: "third world".

Free text search and metadata search

Which search words you choose is crucial, but you should also be aware of what information you are searching in. Are you searching in the whole document text  or only among titles, authors, or other metadata that describes the documents?

Searching in the whole text of documents is usually called free text search, or full text search. A typical example of this is Google. When you are searching in the whole text, you can use specified words that occur in the text.

However, if you are searching, using only the metadata that describes the document, you cannot be as specific.

 

Field search

In most databases you will find advanced search options where you can specify in which field you want to limit your search to. In the example below, you will only retrieve documents where the word democracy occur in titles.

Delimiters

In some cases you need to limit your search result, usually when the search has yielded lots of hits with a great variety of relevance. This is often the case when the database is of a general and multidisciplinary character and covers many different subject areas and publication types.

In contrast to metadata searching, this is something you do after the initial search. In the interfaces of today's databases you will usually be offered a set of delimiters that you can use to limit your search.

Publication type

If you limit by publication type, you can choose to search only for journals or dissertations, for example.

Publication date

When limiting your search by publication date, you can for example find material only within the latest three years.

Subject area

In some cases you can choose among a number of subject areas. The example below is from the database ScienceDirect.

Managing search lists

Pay attention to how search results are presented, if they are sorted by publication date or relevancy. Relevancy means that the database automatically weight which documents are relevant based on your search qriteria. In many databases, you can change settings in order to have the search results presented the way you prefer.

Literature

Feather, J. & Sturges, P. (Eds.). (2003). International encyclopedia of information and library science (2. ed.). London: Routledge.

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Content updated 2016-10-07

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