Literature sources availableThe lit

Literature sources available

The literature sources available to help you to develop a good understanding of, and
insight into, previous research can be divided into three categories: primary (published
and unpublished), secondary, and tertiary (Figure 3.2). In reality these categories
often overlap: for example, primary literature sources, including conference proceedings,
can appear in journals, and some books contain indexes to primary and secondary
literature.
The different categories of literature resources represent the flow of information from
the original source. Often as information flows from primary to secondary to tertiary
sources it becomes less detailed and authoritative but more easily accessible. Recognising
this information flow helps you to identify the most appropriate sources of literature for
your needs. Some research projects may access only secondary literature sources whereas
others will necessitate the use of primary sources. The nature of this information flow is typical of traditional printed publications.
However, the Internet is changing this situation, providing a more direct means of both
publishing and accessing information. Alongside this, moves toward ‘freedom of information’
mean that what were traditionally ‘grey literature’, such as some government publications,
are increasingly being made available, usually via the Internet. The majority of
academic publications still exhibit this information flow, although the final place of publication
is increasingly the Internet.
Figure 3.2 also illustrates the reduced currency of secondary literature sources, which
are utilising information already published in primary sources. Because of the time taken to
publish, the information in these sources can be dated. Your literature review should reflect
current thinking as far as possible, so the limitations of such sources must be recognised.
Primary literature sources are the first occurrence of a piece of work. They include
published sources such as reports and some central and local government publications
such as White Papers and planning documents. They also include unpublished manuscript
sources such as letters, memos and committee minutes that may be analysed as
data in their own right (Section 8.2). It is because primary literature sources can be difficult
to trace that they are sometimes referred to as grey literature.
Secondary literature sources such as books and journals are the subsequent publication
of primary literature. These publications are aimed at a wider audience. They are easier
to locate than primary literature as they are better covered by the tertiary literature.
Tertiary literature sources, also called ‘search tools’, are designed either to help to
locate primary and secondary literature or to introduce a topic. They, therefore, include
indexes and abstracts as well as encyclopaedias and bibliographies.
Your use of these literature sources will depend on your research question(s) and
objectives, the need for secondary data to answer them (Section 8.3) and the time available.
For some research projects you may use only tertiary and secondary literature; for
others you may need to locate primary literature as well. Most research projects will make
the greatest use of secondary literature, and so it is this we consider first, followed by the
primary literature. Tertiary literature sources are not discussed until Section 3.5, as their
major use is in conducting a literature search.