Study Design & Methodology Flashcards

What is the purpose of a research hypothesis?

Answer: To guide the data collection process

A research hypothesis is a testable statement that proposes a relationship between variables, serving as an educated guess about the study's outcome. Its primary purpose is to provide a clear direction for the research, dictating what specific data needs to be collected and how it should be analyzed to either support or refute the proposed relationship. This guides the entire investigative process.

Which study design is best suited for identifying causal relationships?

Answer: Randomized controlled trial (RCT)

A Randomized Controlled Trial (RCT) is considered the gold standard study design for identifying causal relationships. This is because participants are randomly assigned to either an intervention group or a control group, which minimizes bias and ensures that the groups are comparable at baseline. Any significant differences observed between the groups post-intervention can then be confidently attributed to the treatment, establishing causality.

What does a control group help researchers determine in experimental research?

Answer: The effectiveness of the treatment

In experimental research, a control group is crucial because it does not receive the treatment or intervention being studied, serving as a baseline for comparison. By comparing the outcomes of the treatment group to the control group, researchers can isolate the specific effects of the intervention. This allows them to accurately determine the effectiveness of the treatment, ruling out other potential influencing factors.

Why is randomization important in clinical research?

Answer: To eliminate bias and improve validity

Randomization is crucial in clinical research because it ensures that participants are assigned to different treatment groups purely by chance. This process helps to distribute known and unknown confounding factors evenly across groups, thereby minimizing selection bias. By reducing bias, randomization strengthens the internal validity of the study, making it more likely that any observed effects are truly due to the intervention being tested.

What is a confounding variable in research?

Answer: A variable that influences both independent and dependent variables

A confounding variable is an extraneous factor that correlates with both the independent variable (the intervention being studied) and the dependent variable (the outcome being measured). If not accounted for, a confounder can create a spurious association or mask a true one, making it difficult to determine the true cause-and-effect relationship. Researchers must identify and control for confounding variables to ensure the validity of their study findings.

What is blinding in clinical research?

Answer: Concealing treatment assignment from participants or researchers

Blinding in clinical research involves deliberately withholding information about treatment assignments from participants, researchers, or both. This technique is employed to prevent bias that could arise from participants' expectations (placebo effect) or researchers' preconceived notions (observer bias) influencing the study outcomes. Single-blinding conceals assignment from participants, while double-blinding conceals it from both participants and researchers, thereby enhancing the objectivity and validity of the study results.

What is the purpose of a sample size calculation in research design?

Answer: To ensure the study has adequate statistical power

Sample size calculation is a critical step in research design that determines the minimum number of participants needed to detect a statistically significant effect, if one truly exists. Its primary purpose is to ensure the study has adequate statistical power, meaning a high probability of correctly rejecting a false null hypothesis. An insufficient sample size can lead to a study being underpowered, potentially missing important effects and producing inconclusive results.

What is the difference between internal and external validity in research?

Answer: Internal validity is about the study’s accuracy, while external validity is about generalization

Internal validity refers to the extent to which a study accurately establishes a cause-and-effect relationship between the independent and dependent variables, free from confounding factors. External validity, on the other hand, concerns the generalizability of the study's findings to other populations, settings, and times beyond the specific study conditions. A study can have high internal validity but low external validity, meaning its findings are accurate for the study group but may not apply broadly.

Why is ethical approval required in clinical research?

Answer: To protect participants' safety and rights

Ethical approval, typically granted by an Institutional Review Board (IRB) or Ethics Committee, is a mandatory requirement in clinical research. Its fundamental purpose is to safeguard the welfare, rights, and dignity of research participants. This involves reviewing the study protocol to ensure risks are minimized, benefits are maximized, informed consent is properly obtained, and participant privacy and confidentiality are protected.