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Diagnose why this study's design does not qualify as a double-blind study. Identify the specific uncontrolled threat to validity in this research design, and explain how modifying the design to make it double-blind would address this issue.
Case context: A researcher is investigating whether a new cognitive training program improves focus in college students. The researcher randomly assigns participants to either the active cognitive training group or an inactive control group. The participants are not told which group they are in. However, the researcher, who knows each participant's group assignment, personally conducts the training sessions and administers the final focus assessment to collect the study's data.
Question: Diagnose why this study's design does not qualify as a double-blind study. Identify the specific uncontrolled threat to validity in this research design, and explain how modifying the design to make it double-blind would address this issue.
Sample answer: This study does not qualify as a double-blind study because the researcher who interacts with the participants and administers the assessments knows the participants' assigned conditions. Although participant expectations are controlled (making it single-blind), the design fails to control for experimenter bias. The researcher's expectations could unconsciously influence how they conduct the training sessions or score the focus assessments. To make it a double-blind study, the researcher must hire assistants who are kept unaware of the participants' conditions to conduct the sessions and administer the assessments, which would minimize both participant expectations and experimenter bias to ensure the results reflect the true effect of the cognitive training.
Key points:
- The design is not double-blind because the researcher interacting with participants is aware of their assigned conditions.
- The study is vulnerable to experimenter bias during the training and assessment phases.
- A double-blind modification requires keeping the interacting experimenter unaware of the assignments.
- Blinding the interacting experimenter minimizes experimenter bias, ensuring results reflect the true effect of the independent variable.
Rubric: To receive full credit, the student must: 1) Diagnose that the study is not double-blind because the experimenter interacting with participants and conducting assessments is aware of their group assignments. 2) Identify experimenter bias as the uncontrolled threat to validity. 3) Explain that modifying the study to be double-blind requires that both the participants and the interacting experimenter remain unaware of the assignments. 4) Explain that this modification simultaneously minimizes participant expectations and experimenter bias to isolate the true effect of the independent variable.
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Research Methods in Psychology - 4th American Edition @ KPU
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