Russel-Research-Method-in-Anthropology

The Foundations of Social Research 63
Beg people to find potentially spurious relations in your work. You’ll thank
them for it if they do.
Condition 3: Precedence, or Time Order
Besides a nonspurious association, something else is required to establish a
cause-and-effect relation between two variables: a logical time order. Firefighters
don’t cause fires—they show up after the blaze starts. African Americans
have higher blood pressure, on average, than Whites do, but high blood
pressure does not cause people to be African American.
Unfortunately, things are not always clear-cut. Does adoption of new technologies
cause wealth, or is it the other way around? Does urban migration
cause dissatisfaction with rural life, or the reverse? Does consumer demand
cause new products to appear, or vice versa? Does the growth in the number
of lawsuits cause more people to study law so that they can cash in, or does
overproduction of lawyers cause more lawsuits?
What about the increase in elective surgery in the United States? Does the
increased supply of surgeons cause an increase in elective surgery, or does the
demand for surgery create a surfeit of surgeons? Or are both caused by external
variables, like an increase in discretionary income in the upper middle
class, or the fact that insurance companies pay more and more of Americans’
medical bills?
Figure 2.4 shows three kinds of time order between two variables. Read
figure 2.4(a) as ‘‘a is antecedent to b.’’ Read figure 2.4(b) as ‘‘a and b are
antecedent to c.’’ And read figure 2.4(c) as ‘‘a is antecedent to b, which is an
intervening variable antecedent to c.’’ A lot of data analysis is about understanding
and controlling for antecedent and intervening variables—about
which much more in chapter 20.
A
B
A
B
C A B C
a. b. c.
Figure 2.4. Time order between two or three variables.
Condition 4: Theory
Finally, even when you have established nonspurious, consistent, strong
covariation, as well as a logical time sequence for two or more variables, you