RESEARCH METHOD COHEN ok

176 NATURALISTIC AND ETHNOGRAPHIC RESEARCH
convenience sampling: opportunistic sampling,
selecting from whoever happens to be
available
critical-case sampling: e.g. people who display
the issue or set of characteristics in their
entirety or in a way that is highly significant
for their behaviour
identifying the norm of a characteristic: then the
extremes of that characteristic are located, and
the bearers of that extreme characteristic are
selected
typical case-sampling: a profile of attributes
or characteristics that are possessed by an
‘average’, typical person or case is identified,
and the sample is selected from these
conventional people or cases
unique-case sampling: cases that are rare, unique
or unusual on one or more criteria are
identified, and sampling takes places within
these; here whatever other characteristics or
attributes a person might share with others, a
particular attribute or characteristic sets that
person apart
reputational-case sampling: a variant of
extreme-case and unique-case sampling, where
aresearcherchoosesasampleontherecommendation
of experts in the field
snowball sampling: using the first interviewee to
suggest or recommend other interviewees.
Patton (1980) identifies several types of
sampling that are useful in naturalistic research,
including
sampling extreme/deviant cases: in order to gain
information about unusual cases that may be
particularly troublesome or enlightening
sampling typical cases: in order to avoid rejecting
information on the grounds that it has been
gained from special or deviant cases
snowball sampling: one participant provides
access to a further participant and so on
maximum variation sampling: in order to
document the range of unique changes that
have emerged, often in response to the different
conditions to which participants have had to
adapt; useful if the aim of the research is to
investigate the variations, range and patterns in
aparticularphenomenonorphenomena(Ezzy
2002: 74)
sampling according to intensity: depending on
which features of interest are displayed or
occur
sampling critical cases: in order to permit
maximum applicability to others; if the
information holds true for critical cases (e.g.
cases where all of the factors sought are
present), then it is likely to hold true for others
sampling politically important or sensitive cases: to
draw attention to the case
convenience sampling: saves time and money
and spares the researcher the effort of finding
less amenable participants.
One can add to this list types of sample from Miles
and Huberman (1994: 28):
homogeneous sampling: focuses on groups with
similar characteristics
theoretical sampling: in grounded theory,
discussed below, where participants are
selected for their ability to contribute to the
developing/emergent theory
confirming and disconfirming cases: akin to the
extreme and deviant cases indicated by Patton
(1980), in order to look for exceptions to the
rule, which may lead to the modification of the
rule
random purposeful sampling: when the potential
sample is too large, a smaller subsample
can be used which still maintains some
generalizability
stratified purposeful sampling: to identify subgroups
and strata
criterion sampling: all those who meet some
stated criteria for membership of the group or
class under study
opportunistic sampling: to take advantage of
unanticipated events, leads, ideas, issues.
Miles and Huberman (1994) make the point that
these strategies can be used in combination as well
as in isolation, and that using them in combination
contributes to triangulation.
We discuss below two other categories of sample:
‘primary informants’ and ‘secondary informants’