Answer to Question 1
Some of obvious, easy to collect measurements like performance in school or IQ test scores do not show consistent or permanent changes among the participants in Head Start programs. These variables lead to a conclusion that the program does not meet its intended goals. On the other hand, longer-term measurements like high school graduation rates, dependence on public assistance, and participation in criminal activity reveal that Head Start participants fare better than those who did not participate. Depending on your choice of your variables, you could wind up with conclusions that are contradictory. The variables of interest need to be chosen carefully so they help you answer your research question.
Answer to Question 2
a. Because much social and behavioral research involves student populations and because students as a whole constitute a relatively homogeneous population, the diversity among research participants is typically very limited.
b. It takes extra time, effort, money, etc. to recruit participants who are not students or who form a diverse group; researchers often do not have the resources for studying participants who are not readily available.
c. Some researchers believe that we need to study at least three different cultures in order to be able to find out what behaviors reliably emerge and in what circumstances. With every additional component of research, it becomes more difficult to conduct.
d. Researchers may not be adequately trained to study behaviors in cultures other than their own, so their interpretations of data and of the behaviors themselves may be biased toward their own cultural perspective.
e. Because social scientists study behaviors, which are affected by culture and society, we have to account for differences across those we study. Scientists in the physical sciences do not have such problems, so they can use the same methodologies without any problems. Researchers in the natural sciences sometimes need to consider diversity if they study behaviors or characteristics across species of plants or animals.
Head Region of a Beetle
head
Frog head muscle (labeled)
(A) Female head louse. (Courtesy of the Centers for Disease Control and Prevention/ Dr. Dennis ...
Head of a patient with tertiary syphilis.
National lead measurements, 1984 - 2008