Chapter 4. Searching for Information
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It has been estimated that the average scientist uses up to 20% of his
or her time for information retrieval. It is therefore very important that
you learn to do this efficiently!
4.1 Types of information searches
There are different kinds of information needs, and these can be met by
different types of information search:
Retrospective information retrieval
Current awareness searches
Searching forwards from a known citation (reference)
4.1.1 Retrospective information retrieval - Following up published research
There is a need for information on previous work within a given subject
area when you are starting a new project. This can be met by the Retrospective
Information Search. Retrospective searches vary in depth, ranging from
a preliminary background search in connection with a new project, to a
comprehensive investigation of all the total available information, in
connection with a research thesis.
This type of search is used when you need background information on a specific
subject area. It is often used by students in connection with projects.
It is possible to obtain background information through textbooks, encyclopaedias,
research reviews and indexes and abstracts in either print form, or on
CD-ROM or online.
The need for comprehensive information arises when you are about to start
research work on an extensive project and do not wish to repeat work that
has already been done! The term "extensive" is in all senses relative -
there is a point where the time consumed and the cost for further information
retrieval must act as limiting factors.
4.1.2 Current Awareness Searching - Keeping up-to- date
Scientists and engineers need to keep up-to-date with progress in their
own disciplines and within related areas. This can be achieved by Current
Awareness searching, which can be carried out in a number of ways:
The traditional method is to regularly scan a small number of highly relevant
primary publications (journals) which are judged to be of central importance
within your subject field. This method is relatively time-consuming and,
if used alone, involves the time-delay between the actual research and
publication in journal article form (see Fig.5).
A modern method is to make use of online Current Awareness databases that
are frequently available via the campus network or via the Internet. These
databases contain Tables of Contents of journals and other publications.
They are usually updated at least once a week. Examples are Inside Information,
produced by the British Library, and Uncover, produced by the Colorado
Association of Research Libraries and Blackwells. Searching is carried
out on a computer or terminal connected to a communication network
Current awareness searching of journals can also be handled by means of
special Current Awareness publications which contain the Tables
of Contents of a large number of discipline-oriented journals. Examples
of such publications are Current Contents. Engineering, Technology and
Applied Sciences, covering some 750 journals, and Current Contents.
Physical, Chemical & Earth Sciences. The latter includes the contents
of more than 900 journals within the subjects of physics, mathematics,
chemistry and earth sciences. The time delay after publication in the primary
journals is usually very short, being between one and two weeks. There
is a subject index and an author index, which contains addresses to facilitate
requests for reprints. These publications are today available in both print
and machine-readable form (on disks or as online databases) and are distributed
on a weekly basis. Another tool for current awareness searching is Page
1, published by Engineering Information. Page 1 provides the contents
from a wide range of journals and conference reports within the fields
of the engineering sciences, and is distributed as a CD-ROM on a monthly
basis or available as an online database.
It is also possible to use computerised SDI - Selective Dissemination
of Information, for a specified subject area. You can formulate a search
enquiry which can be matched against information stored in one or more
databases, at regular intervals. References which contain the specified
terms are printed out (or provided on diskette). This SDI search is carried
out periodically - searching for the new material that is added to the
database(s) specified. There is a charge for SDI services.
4.1.3 Citation searching
The citation index is an entirely different type of index, which allows
you to search forwards in time from a known relevant paper. In every
field of scholarship, research workers and practitioners cite references
to earlier publications related to the work described in their own papers.
Through these references (citations) an author expresses subject relationships
between the current article and the cited references. A citation index
is based on these relationships. It lists publications that have been cited
and identifies the sources of these citations. Starting from a known relevant
reference, it is possible to trace subsequent articles which refer to the
original document, thus leading to more recent literature than the first
known item. Citation indexes are designed to facilitate searching forwards
in time from a known relevant paper.
The Science Citation Index - SCI - covers over 5 600 journals
in a wide range of subjects in the physical and natural sciences, medicine
SCI consists of three main parts:
Citation indexes are extremely useful tools for "working forwards" from
a highly relevant reference. In using them, it is, however, important to
bear in mind the normal pattern of citation. There is a time-lag between
the publication of a document and the first reference to it, due to the
time taken to assimilate the new information, the time taken to make use
of it in further research and the time taken to publish the citing document.
The citation index is a powerful tool for information retrieval, in that
it is possible to use a cyclic technique, in which the citing document
found, together with other papers by the same author (s), may act as new
search entry points. ISI provide annual user guides for Science Citation
Index, as well as lists of the journals covered. These are arranged alphabetically,
by subject and by country of publication. The equivalent database - SciSearch
is available on the Data-Star and DIALOG information retrieval systems,
as well as via the Bath Information and Data Services - BIDS - in the United
Citation Index -
every reference (citation) from the articles in the Source Index, that
are being referred to (or cited) during a given period of time is listed
in alphabetical sequence under the name of the first author;
Source Index -
an alphabetically arranged author index, giving full bibliographic details
of all the source publications; journal articles, reviews, books etc. are
indexed by the first author (with references from other authors);
Permuterm Index -
a subject index in which every significant word in the title of every article
being indexed is paired with every other significant word in the title
and rotated (e.g. AB, BA).
4.1.4 Searching for facts
The need forfactual information often arises during the work process and
usually takes the form of a specific information requirement in order to
continue working. This type of specific information can be found in handbooks,
tables, charts, dictionaries, and factual data-banks. You need a quick
and reliable answer to a query - for example, the melting point of an alloy
or the characteristics of a certain component. Handbooks and tables are
renewed at frequent intervals, so make sure that you are using the most
Browsing is a form of random literature searching for information, in which
you select and scan material within a mass of available literature. This
type of search is often carried out outside your usual field of interest.
This unplanned random information searching can serve as a stimulus and
can be a very fruitful source of new ideas.
4.2 The search process
The first stage of the retrospective information search, the current awareness
search and the factual search is to know what you are looking for.
This sounds easy, but many people starting on a project experience difficulty
in both deciding on the topic and defining the true information needs.
When faced with the task of deciding on a research topic, you have to
weigh possible topics against criteria of personal interest, information
available, the possibility of good supervision and the time available for
the task. This is not always very easy. One of the strategies involves
making a preliminary information search to get a rough idea of the kind
and amount of information that is available. Many students experience both
anxiety and confusion until the topic is selected, but this usually changes
to anticipation once a decision is reached. Having decided on a topic,
you will need to make a more detailed information search. You do this in
a series of stages (see Fig.11):
Lack of precision in defining the real information need can lead to poor
search results. The relationship between the true information needs and
the search construction is illustrated in Fig. 12. It can be seen that
the expressed needs are not always the real needs, and this can lead to
the retrieval of only a few relevant documents and much irrelevant material.
At all stages, it is necessary to make use of feedback and to evaluate
Formulate the search question in a clear and concise search statement.
Analyse the search question into component aspects, which can be represented
by keywords or descriptors (search terms).
Develop and expand the search statement by means of synonyms, broader terms
and terms related to the descriptors, so that all possible aspects are
covered. Tools to be used in this development process are dictionaries,
thesauri, encyclopaedias, handbooks etc. Known relevant articles and references
can orovide valuable starting-points.
Limit the search to suit the purpose of the search (project, application,
thesis etc.), the subject area and the time span required.
Choose the appropriate tools for information retrieval - library catalogues,
research reviews, secondary publications, databases etc.
Search for the relevant information.
Evaluate the results of the search.
If necessary, modify and alter the search strategy.
Fig. 11. Diagrammatic representation of the search process.