Study Designs – Randomized Controlled Trials MCQ Quiz | Epidemiology

Welcome to the quiz on Randomized Controlled Trials (RCTs), the gold standard in clinical research. This quiz is designed for MBBS students to test their understanding of the fundamental principles of RCTs within the field of Epidemiology. You will be tested on key concepts such as randomization, blinding, intention-to-treat analysis, clinical trial phases, and ethical considerations. This exercise will help solidify your knowledge and prepare you for examinations. There are 25 multiple-choice questions. After submitting your answers, you will see your score, and the correct and incorrect answers will be highlighted. You can also download a PDF copy of all the questions along with their correct answers for your future reference and study. Good luck!

1. What is the primary purpose of randomization in a Randomized Controlled Trial (RCT)?

To ensure that participants are blind to their treatment allocation.

To create comparable groups and eliminate selection bias.

To make the study easier to analyze statistically.

To ensure that all participants receive the new intervention.

2. The term ‘blinding’ or ‘masking’ in an RCT is used to reduce:

Selection bias

Confounding

Observer and subject bias

Attrition bias

3. In a double-blind trial, who is unaware of the treatment allocation?

Only the participant

Only the investigator

Both the participant and the investigator

The participant, investigator, and data analyst

4. The ethical principle that requires genuine uncertainty about the preferred treatment before an RCT can begin is known as:

Beneficence

Justice

Informed consent

Clinical equipoise

5. An “intention-to-treat” (ITT) analysis means:

Only participants who completed the treatment are analyzed.

All participants are analyzed in the groups to which they were originally randomized.

Participants who dropped out are excluded from the final analysis.

Analysis is based on the treatment actually received, not the assigned one.

6. Which phase of a clinical trial primarily focuses on establishing the efficacy of a new drug against a placebo or standard treatment in a large group of patients?

Phase I

Phase II

Phase III

Phase IV

7. A “crossover” design in an RCT involves:

Participants choosing which treatment they prefer to cross over to.

Each participant receiving all treatments in a sequential order.

Two separate groups being studied in parallel without any crossover.

The control group crossing over to the treatment group after the study ends.

8. What is the main advantage of a factorial design in an RCT?

It requires fewer participants than a standard parallel design.

It eliminates the need for a placebo group.

It allows for the evaluation of two or more interventions simultaneously.

It is the only design suitable for surgical trials.

9. A placebo is used in an RCT to:

Account for the non-specific psychological and physiological effects of treatment.

Ensure that the treatment group shows a better outcome.

Test the long-term toxicity of a new drug.

Increase the sample size of the study.

10. Loss to follow-up in an RCT can lead to what type of bias?

Recall bias

Selection bias

Attrition bias

Observer bias

11. The process of obtaining voluntary agreement from a person to participate in a study, after they have understood all the relevant information, is called:

Randomization

Blinding

Informed consent

Ethical review

12. Which of the following is considered the “gold standard” in evidence-based medicine for evaluating the effectiveness of an intervention?

Case-control study

Cohort study

Randomized Controlled Trial

Cross-sectional study

13. What does a p-value of < 0.05 typically signify in the context of an RCT’s primary outcome?

The observed difference is clinically important.

There is a greater than 95% chance the intervention is effective.

The observed difference is statistically significant and unlikely to be due to chance.

The study has a low risk of bias.

14. A ‘run-in’ period before randomization in an RCT is sometimes used to:

Increase the total duration of the study.

Identify non-compliant or ineligible participants.

Randomize participants more effectively.

Allow participants to choose their preferred treatment.

15. Which type of RCT design is most appropriate for evaluating an intervention that cannot be reversed, like a surgical procedure?

Crossover design

Factorial design

Parallel group design

Pre-post design

16. The statistical power of an RCT is the probability of:

Incorrectly concluding that an effect exists (Type I error).

Correctly concluding there is no effect when one truly does not exist.

The study results being published in a high-impact journal.

Correctly detecting a true effect if one exists.

17. Which body is typically responsible for overseeing the ethical conduct and safety of an RCT?

The pharmaceutical sponsor

The principal investigator’s own team

Institutional Review Board (IRB) or Ethics Committee

The Food and Drug Administration (FDA)

18. In an “open-label” trial:

Only the data analyst knows the treatment allocation.

Both participants and investigators know the treatment allocation.

No one knows the treatment allocation until the study is over.

Only the participant knows their treatment allocation.

19. What is the primary limitation of RCTs?

They cannot establish causality.

They are highly susceptible to confounding bias.

They may have limited generalizability to real-world clinical practice.

They are always less expensive than observational studies.

20. A “surrogate endpoint” in an RCT is:

The main outcome that is of direct clinical relevance to the patient.

An outcome measured on a family member instead of the patient.

A laboratory measurement or physical sign used as a substitute for a clinically meaningful endpoint.

An endpoint that is decided after the study has concluded.

21. Block randomization is a technique used to:

Ensure that investigators are blocked from seeing the allocation sequence.

Ensure a balance in the number of participants in each group throughout the recruitment period.

Group participants with similar characteristics into blocks.

Prevent certain blocks of participants from being enrolled in the study.

22. Which phase of clinical trials is conducted after a drug has been approved and is on the market, often called post-marketing surveillance?

Phase I

Phase II

Phase III

Phase IV

23. A Type I error (alpha) in an RCT occurs when:

The study concludes there is no effect when, in reality, there is an effect.

The study concludes there is an effect when, in reality, there is no effect.

The sample size is too small to detect a real effect.

The study protocol is violated by participants.

24. Stratified randomization is used to:

Ensure that important prognostic factors are balanced between treatment groups.

Make the randomization process simpler and faster.

Allow participants to be stratified into high-risk and low-risk groups after the study.

Create treatment groups of unequal sizes deliberately.

25. The CONSORT statement provides guidelines for:

The ethical conduct of observational studies.

Analyzing data from cohort studies.

Reporting the methodology and results of randomized controlled trials.

Designing case-control studies to minimize bias.

Study Designs – Randomized Controlled Trials MCQ Quiz | Epidemiology

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