Each of these categorizations of evaluation approaches or theories provides
useful insights into evaluation and its history and practice. Thus, Shadish, Cook,
and Leviton illustrate the early focus on the truth that evaluation would bring to
the judgments made about social programs, the later recognition that use needed
to be consciously considered, and the integration and adaptation of the two issues
in even later stages. Alkin and Christie's model builds on these foundations identified
by Shadish et al. in slightly different ways. Its roots are in social inquiry,
accountability, and control, but it considers evaluation's emphases in three areas:
methods, values, and use. Stufflebeam's categories are different from the first two
in that he focuses not on individual evaluators and their writings to identify categories,
but on the content of evaluation theories or models.He developed his categories
by considering the orienting devices or principles used for focusing the
evaluation. The priorities used to focus the evaluation are reflected in his three
categories: using particular evaluation questions or methods, taking a comprehensive
approach to making a judgment regarding quality of the program, or
improving society and its programs by considering social equity and the needs of
those with less power. Like Stufflebeam, our purpose is to reduce the current
number of evaluation approaches. Although Stufflebeam's method of reducing
the approaches was to judge the quality of each, our synthesis of the approaches
is intended to describe each approach to help you, the reader, to consider different
approaches and their potential use in your work. Although the many different
approaches to evaluation can seem confusing, their diversity allows evaluators to
pick and choose either the approach or the elements of an approach that work best
for each program they are evaluating. Our task is to categorize the approaches in
a way that helps you consider them and to expand your views of possible ways in
which evaluations may be conducted.