Apply What You Have Learned
You’ve come a long way in your understanding of how studies are designed and evidence is
reported. Review Chun, Kim, and Park (2015) and Fakhry, Hannah, Anderson, Holmes, and
Nathwain (2012). Also read Huis et al. (2013) and Al-Hussami, Darawad, and Almhairat (2011). Cite
these in APA style, and complete the intervention and comparison columns of the grid. Look at
the examples to see what information is needed to complete these columns.» Experimental designs provide the best evidence of cause-and-effect relationships. These types
of designs must include three features: randomization, control, and manipulation. There are six
types of experimental designs: two-group pretest-posttest, two-group posttest-only, Solomon
four-group, multiple-experimental groups, factorial, and crossover designs.
» Quasi-experimental designs involve manipulation of the IV but do not meet one of the other
criteria for experimental designs. Three common quasi-experimental designs are nonequivalent
control group pretest-posttest, one-group time series, and preexperimental designs.
» In nonexperimental designs, the IV is not manipulated; therefore, cause and effect cannot be
established. These types of designs are used to explore phenomena when the information is scant.
Descriptive designs and correlational designs are two major types of nonexperimental designs.
» Researchers must consider maintaining standards of care and the benefits and risks of study
participation when designing quantitative studies.
» Quantitative designs can be used in translational research, community-based participatory
research, and health services research.RAPID REVIEW
Which of the following situations is unethical?- A researcher tells a subject that he will not receive as high quality care if he withdraws
from the study. - A research assistant carefully explains in English, without using an interpreter, the
benefits and risks of being in a study to a woman who speaks only Spanish. - After discovering that subjects are experiencing adverse reactions to an intervention,
researchers agree to discontinue the study.
TEST YOUR KNOWLEDGE 7-5
How did you do? 1. Unethical; 2. Unethical; 3. Ethical190 CHAPTER 7 Quantitative Designs: Using Numbers to Provide Evidence