A controlled experiment and a quasi-experiment.
Address the following listed items:
Create a table that portrays the similarities and differences between a controlled experiment and a quasi-experiment.
Describe how you would conduct a nested case-control study of low socioeconomic status as a risk factor for teenage pregnancy.
Explain what is meant by the statement that cohort studies overcome the problem of temporality, which is not addressed by other types of observational study designs. You satisfy temporality of cause and effect, one of the causal criteria—not done in other observational studies.
What are some of the practical issues that influence the design of a cohort study?
Explain the purposes of blinding and randomization in clinical trials.
Describe the phases of a clinical trial to license a vaccine or new medicine.
What is meant by a crossover design? Distinguish between a planned and unplanned crossover.
Sample Solution
An experiment is a study in which the researcher manipulates the level of some independent variable and then measures the outcome. There are two basic types of research design: controlled/true experiments and quasi experiments. The purpose of both is to examine the cause of certain phenomena. Like a true experiment, a quasi-experimental design aims to establish a cause-and-effect relationship between an independent and dependent variable. However, unlike a true experiment, a quasi-experiment does not rely on random assignment. Instead, subjects are assigned to groups based on non-random criteria. In a true experiment, participants are randomly assigned to either the treatment or the control group, whereas they are not assigned randomly in a quasi-experiment.
