SUBJECTS AND SAMPLING
generalizing the results. Hence it is
to understand who the
subjects are and how they
INTRODUCTION TO SAMPLING What Is a Subject?
A subject is an individual who participates in a research study or is some- one from whom data are collected. In experiments, for example, each person who is given a treatment and whose behavior is measured is con- sidered to be a subject. The term subject may also identify individuals whose behavior, past or present, is used as data, without their involve-
subject: person from ,++,om data are
ment in some type of treatment or
For instance, a re-
searcher might use last year’s fourth-grade test scores
data, and each
fourth-grader included is considered to be a subject. In qualitative re-
search individuals are identified as
rather than subjects.
What Is a Population?
is a group of elements or cases, whether individuals,
conform to specific criteria and to which we intend
~opu~ion: PWSOW to whom IwItS can be
to generalize the results of the research. This group is also referred to as
The specification of the population be-
gins with the research problem and review of literature, through which a population is described conceptually or in broad terms, for example, seventh-grade students, beginning teachers, principals, special educa- tion teachers, and so forth. A more specific definition is then needed, based on demographic characteristics. These characteristics are some-
times referred to as
For example, in a study of
grade minority students, there are three delimiting characteristics: stu- dents, first grade (age), and minority. Further delimiting variables should be added to provide as precise a definition possible. What about geographic region, socioeconomic status, gender, type of commu- nity, and types of schools? Are both public and private students in- cluded? How is “minority” defined? It is also important to distinguish the target population from a list of elements from which a group of sub jects is selected, which is termed the population In a study of beginning teachers, the target population may be begin- ning teachers across the United States, in all of schools. The survey population may be a list of beginning teachers that was obtained from
four states. Although the intent may be all beginning teachers, the
are limited, or delimited, to beginning teachers in the four states. Thus, generalization from subjects to populations should be based on the survey population.