Russel-Research-Method-in-Anthropology

58 Chapter 2
‘‘Life satisfaction’’ is another very complex variable, composed of several
concepts—like ‘‘having sufficient income,’’ ‘‘a general feeling of well-being,’’
and ‘‘satisfaction with level of personal control over one’s life.’’ In fact, most
of the really interesting things that social scientists study are complex constructs,
things like ‘‘quality of life,’’ ‘‘socioeconomic class,’’ ‘‘ability of teenagers
to resist peer pressure to smoke,’’ and so on.
Construct Validity
An instrument has high construct validity if there is a close fit between
the construct it supposedly measures and actual observations made with the
instrument. An instrument has high construct validity, in other words, if it
allows you to infer that a unit of analysis (a person, a country, whatever) has
a particular complex trait and if it supports predictions that are made from
theory.
Scholars have offered various definitions of the construct of ethnicity, based
on different theoretical perspectives. Does a particular measure of Mexican
American ethnicity have construct validity? Does it somehow ‘‘get at,’’ or
measure, the components of this complex idea?
Asking people ‘‘How old are you?’’ has so much face validity that you
hardly need to ask whether the instrument gets at the construct of chronological
age. Giving people an IQ test, by contrast, is controversial because there
is so much disagreement about what the construct of intelligence is. In fact,
lots of constructs in which we’re interested—intelligence, ethnicity,
machismo, alienation, acculturation—are controversial and so are the measures
for them. Getting people to agree that a particular measure has high construct
validity requires that they agree that the construct is valid in the first
place.
Criterion Validity: The Gold Standard
An instrument has high criterion validity if there is a close fit between the
measures it produces and the measures produced by some other instrument
that is known to be valid. This is the gold standard test.
A tape measure, for example, is known to be an excellent instrument for
measuring height. If you knew that a man in the United States wore shirts with
35 sleeves, and pants with 34 cuffs, you could bet that he was over 6 tall
and be right more than 95% of the time. On the other hand, you might ask:
‘‘Why should I measure his cuff length and sleeve length in order to know
most of the time, in general, how tall he is, when I could use a tape measure
and know all of the time, precisely how tall he is?’’