Question

(Select all that apply.)
a. The experimental design controls for more variables.
b. Subjects are blind to group assignment in the experimental design.
c. There is now a means of two-group comparison.
d. The design controls for changes due to maturation or history.
e. The researcher collects data more frequently.

Answer 1

ANS: A, C, D
The one-group pretest-posttest design is one of the more commonly used quasi-experimental designs. However, it has such serious weaknesses that findings are often uninterpretable. Pretest scores cannot adequately serve the same function as a comparison group. Events can occur between the pretest and posttest that alter responses to the posttest. The original, or classic, experimental design, or pretest-posttest control group design, is still the most commonly used experimental design. There are two randomized groups, one receiving the experimental treatment and one receiving no treatment, a placebo treatment, or the routine or standard care. By comparing pretest scores and the groups' demographic characteristics, one can evaluate the effectiveness of randomization in providing equivalent groups. The researcher implements the treatment or independent variable under very controlled conditions. The dependent variable is measured twice, before and after the manipulation of the independent variable.

Answer 2

ANS: A, C, E, F
The rationale for using a design in which subjects act as their own controls is that whatever is being measured varies quite a bit between persons, and the researcher is more interested in showing a change in the subjects than producing a given number value; because of this, a separate control group makes little sense. Examples of this are pain, nausea, and panic. If subjects act as their own controls, they must be measured at least once in the control condition and at least once in the experimental condition. Experimental research requires a separate control group; some quasi-experimental research allows subjects to act as their own controls. Correlational and descriptive research does not use controls—it uses comparison subjects. Quasi-experimental research is interventional.

Answer 3

ANS: A
Methodological designs are used to develop the validity and reliability of instruments to measure constructs used as variables in research. The process is lengthy and complex and should begin with a thorough literature review. Qualitative data is often collected when there is not much known about a construct and will allow the researcher to identify key factors/concepts associated with the construct which might be used to create a checklist.
Validity refers to a tool's ability to measure what the researcher intends it to measure.

Answer 4

ANS: C, E
A merger of the cross-sectional or longitudinal and trend designs, the event-partitioning design, is used in some cases to increase sample size and to avoid the effects of history on the validity of findings. Cook and Campbell referred to these as cohort designs with treatment partitioning. The term treatment is used loosely here to mean a key event that is thought to lead to change. In a descriptive study, the researcher would not cause or manipulate the key event but rather would clearly define it so that when it occurred naturally, it would be recognized. Data across subjects is assumed to be comparable, and a larger sample size would be available for later studies of changes over time.

Answer 5

ANS: A, B, D
Crossover, or counterbalancing, is a strategy designed to guard against possible erroneous conclusions resulting from carryover effects. With counterbalancing, subjects are randomly assigned to a specific sequencing of treatment conditions. This approach distributes the carryover effects equally throughout all the conditions of the study, thus canceling them out. The carryover effect, in this case, was pain related to healing and pain expectation.