CPI Clinical Research & Study Design 2

Question 1

In a crossover trial, what is the primary purpose of the washout period?

Accepted Answer

To eliminate carryover effects from the first treatment

Answer

The washout period ensures the first treatment is cleared from participants before they receive the second, preventing carryover bias.

Question 2

Which study design is most appropriate for evaluating a rare adverse event that occurs in 1 in 10,000 patients?

Accepted Answer

Case-control study

Answer

Case-control studies start with the outcome (rare event) and look backward, making them efficient for studying rare adverse events.

Question 3

What does the term 'intention-to-treat' (ITT) analysis mean?

Accepted Answer

All randomized participants are analyzed in the group they were assigned to, regardless of adherence

Answer

ITT analysis preserves randomization integrity by including all participants in their assigned groups, even if they did not complete or adhere to the assigned treatment.

Question 4

A study reports an odds ratio of 0.5 for a drug compared to placebo. How should this be interpreted?

Accepted Answer

The drug is associated with 50% lower odds of the outcome

Answer

An OR of 0.5 means the odds of the outcome in the drug group are half (50% lower) compared to the placebo group.

Question 5

Which allocation concealment method best prevents selection bias in an RCT?

Accepted Answer

Centralized randomization via a telephone or web system

Answer

Centralized randomization systems are inaccessible to enrolling investigators, providing the strongest protection against selection bias.

(CPI) Certified Physician Investigator Practice Test

(CPI) Certified Physician Investigator Practice Test

CPI Clinical Research & Study Design 2