| Population Sampling |
| Specific sampling principles and techniques used in survey research are not
necessarily relevant to person sampling in Q-methodology given the contrasting
research orientation and purpose. Participant selection can be governed by
theoretical (persons are chosen because of their special relevance to the
goals of the study, or purposive sampling) or by pragmatic (anyone will
suffice, or convenience sampling) considerations. Because of its intensive
orientation, Q-methodology tends to use person samples that are small, and
single case studies; a preference in keeping with the behaviorist dictum that
it is more informative to study one subject for 1,000 hours than 1,000
subjects for 1
hour.3
|
| Validity |
| Due to its qualitative aspects, questions of research validity in
Q-methodology are assessed differently than in quantitative research
methods.29 The
Q-sorting operation is wholly subjective in the sense that it represents
my point of view. There is no external criterion by which to appraise
an individual's
perspective.1 Each
individual's rank-ordered set of statements is considered a valid expression
of their opinion.
|
| Content validity of the Q-sample is addressed by thorough literature review
and by eliciting expert advice of those associated with the field under
investigation. Face validity of the text and statement wording is addressed by
leaving the statements in the participants' words, edited only slightly for
grammar and readability.
|
| Item validity, as understood in more traditional survey research, does not
apply to the study of subjectivity. In Q-methodology, one expects the meaning
of an item to be interpreted individually. The meaning of how each item was
individually interpreted becomes apparent in the rank-ordering and in
follow-up interviews.
|
| Reliability |
| Reliability of Q-methodology has been proven through test-retest studies and
assessment of reliable schematics. For test-retest reliability, studies have
shown that administering the same instrument (Q-sample) to the same
individuals at two points in time have typically resulted in correlation
coefficients of.80 or
higher.2,30,31,32
Q-methodology has also produced consistent findings in two more types of study
comparisons: first, when administering the same set of statement to different
person samples; and second, when pursuing the same research topic, but using
different sets of statements and different person
samples.28,30,31,32,33
For reliability and stability of identified opinion clusters (schematics),
findings were consistent when the instrument was administered to different
person samples, and even when different Q-samples and person samples were
used.33
|
| Generalizability |
|
Most Q-methodology studies are exploratory and qualitative in nature and tend
not to use random sample designs. Generalizations rarely occur beyond the
immediate set of participants and are typically not based on the numerical
distribution of study participants among factors. The value of Q-methodology
lies in uncovering valid and authentic opinion clusters and does not occur
beyond the immediate set of participants. The value of Q-methodology lies in
uncovering opinion clusters. Once identified, their prevalence among the
larger population can be subsequently tested using large group surveys and
standard variance analytic methods. The purpose of a typology is not the
creation of an exhaustive classification scheme but to find something in the
material worthy of classification, and to provide some of the
categories.34
|
