Randomisation Blinding Sample Size Calculations flashcards

What are the fundamentals of design for major randomized controlled trials?

Choice of patients and centers, treatments, outcomes, randomization, blinding, and sample size.

Why is randomization important in clinical trials?

To eliminate bias and ensure treatment groups do not differ systematically.

What is allocation concealment in the context of randomization?

Ensuring that the person randomizing patients does not know which treatment they will receive before allocation.

What does it mean to conduct a trial double-blind?

Neither the doctor nor the patients know who receives the treatment.

What is minimization in randomization?

A method used to balance treatment groups on many factors by incorporating a random element.

What is the primary aim of blinding in clinical trials?

To ensure that study groups only differ with respect to the treatment they receive, not by anyone's expectations about the treatment.

What are some common stratification factors in randomized trials?

Center/region/country, disease stage, age, sex, and disease markers.

Why is sample size crucial in clinical trials?

Too few patients may miss important treatment effects; too many can be unethical and lead to unnecessary risk.

What are Type I and Type II errors in hypothesis testing?

Type I error (false positive): rejecting the null hypothesis when it is true; Type II error (false negative): failing to reject the null hypothesis when it is false.

What factors affect sample size calculations in clinical trials?

Significance level (α), power (1 - β), effect size (Δ), and variability (σ²).

How would you define a double dummy trial?

A trial comparing two active treatments, where participants take two sets of treatments to keep them blinded.

What is the significance of power in hypotheses testing?

Power is the probability of correctly rejecting the null hypothesis when the alternative hypothesis is true.

What does 'unequal randomization' refer to in clinical trials?

Having treatment groups of unequal sizes, often for better safety profile knowledge of a new drug.

What are continuous and binary outcome measures?

Continuous outcomes are numerical and can take any value, while binary outcomes have two categories (e.g., success/failure).

What is the purpose of a hypothesis in clinical trial research?

To define statements that can be tested statistically to determine the effect of a treatment.

How can loss to follow-up affect sample size calculations?

Sample size can be adjusted for expected loss to follow-up to ensure sufficient numbers remain for analysis.

Why might blinding not be feasible in some trials?

Because certain interventions, like surgery or specific therapies, may not allow for effective blinding.

What is an active comparator in the context of treatment trials?

A control treatment that is an established therapy rather than a placebo.