RESEARCH METHOD COHEN ok

148 VALIDITY AND RELIABILITY
by assigning items one to ten to one half and items
eleven to twenty to the second half, may assign all
the even numbered items to one group and all the
odd numbered items to another. This would move
towards the two halves being matched in terms of
content and cumulative degrees of difficulty.
An alternative measure of reliability as internal
consistency is the Cronbach alpha, frequently
referred to as the alpha coefficient of reliability, or
simply the alpha. The Cronbach alpha provides a
coefficient of inter-item correlations, that is, the
correlation of each item with the sum of all the
other relevant items, and is useful for multi-item
scales. This is a measure of the internal consistency
among the items (not, for example, the people). We
address the alpha coefficient and its calculation in
Part Five.
Reliability, thus construed, makes several
assumptions, for example that instrumentation,
data and findings should be controllable,
predictable, consistent and replicable. This
presupposes a particular style of research,
typically within the positivist paradigm. Cooper
and Schindler (2001: 218) suggest that, in
this paradigm, reliability can be improved by
minimizing any external sources of variation:
standardizing and controlling the conditions under
which the data collection and measurement take
place; training the researchers in order to ensure
consistency (inter-rater reliability); widening the
number of items on a particular topic; excluding
extreme responses from the data analysis (e.g.
outliers, which can be done with SPSS).
Reliability in qualitative research
While we discuss reliability in qualitative research
here, the suitability of the term for qualitative
research is contested (e.g. Winter 2000; Stenbacka
2001; Golafshani 2003). Lincoln and Guba (1985)
prefer to replace ‘reliability’ with terms such as
‘credibility’, ‘neutrality’, ‘confirmability’, ‘dependability’,
‘consistency’, ‘applicability’, ‘trustworthiness’
and ‘transferability’, in particular the notion
of ‘dependability’.
LeCompte and Preissle (1993: 332) suggest that
the canons of reliability for quantitative research
may be simply unworkable for qualitative research.
Quantitative research assumes the possibility of
replication; if the same methods are used with the
same sample then the results should be the same.
Typically quantitative methods require a degree
of control and manipulation of phenomena. This
distorts the natural occurrence of phenomena (see
earlier: ecological validity). Indeed the premises of
naturalistic studies include the uniqueness and
idiosyncrasy of situations, such that the study
cannot be replicated – that is their strength rather
than their weakness.
On the other hand, this is not to say that
qualitative research need not strive for replication
in generating, refining, comparing and validating
constructs (see http://www.routledge.com/
textbooks/9780415368780 – Chapter 6, file 6.7.
ppt). Indeed LeCompte and Preissle (1993: 334)
argue that such replication might include repeating
the status position of the researcher
the choice of informant/respondents
the social situations and conditions
the analytic constructs and premises that are
used
the methods of data collection and analysis.
Further, Denzin and Lincoln (1994) suggest that
reliability as replicability in qualitative research
can be addressed in several ways:
stability of observations: whether the researcher
would have made the same observations and
interpretation of these if they had been
observed at a different time or in a different
place
parallel forms: whether the researcher would
have made the same observations and
interpretations of what had been seen if he
or she had paid attention to other phenomena
during the observation
inter-rater reliability: whether another observer
with the same theoretical framework and
observing the same phenomena would have
interpreted them in the same way.
Clearly this is a contentious issue, for it is seeking
to apply to qualitative research the canons of