3- Randomized Control Trials (RCTs)

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What is an important feature of Randomized Control Trials (RCTs)?

Observation without intervention
Presence of an intervention (correct)
Non-random allocation of participants
Investigator uninvolvement

What is the role of blinding in Randomized Control Trials?

To prevent bias by keeping participants uniformed (correct)
To introduce bias by revealing the intervention
To increase internal validity
To reduce the number of study groups

Why are Randomized Control Trials considered the 'Gold Standard' in epidemiologic study designs?

Due to their higher internal validity compared to other designs (correct)
They involve non-random allocation
Because they do not require follow-up
They have fewer study arms

What is the process that involves assigning participants to different study groups randomly in an RCT?

Randomization (C) Signup and view all the answers

What is the last step in conducting a Randomized Control Trial (RCT) after enrolling participants and random allocation?

Determining the outcome (C) Signup and view all the answers

What is the purpose of random allocation in a study?

To eliminate selection bias and balance confounders between groups (B) Signup and view all the answers

What is the purpose of a comparison group in a randomized control trial?

To serve as a control benchmark against the active treatment group (A) Signup and view all the answers

Why is it important for participants to fulfill eligibility criteria before enrolling in a study?

To minimize confounders between different study groups (C) Signup and view all the answers

What is the purpose of a placebo in a study?

To serve as an inert agent for comparison with the active treatment (C) Signup and view all the answers

Why is unbiased assignment to treatment groups crucial in a study?

To eliminate selection bias and achieve comparable groups (B) Signup and view all the answers

What is the primary goal of using a placebo in a study?

To minimize bias (C) Signup and view all the answers

In a single-blinded study, the result of random allocation is concealed from which group?

Study subjects (D) Signup and view all the answers

What is the main reason for implementing double blinding in a study?

To prevent biases on the part of the investigator (A) Signup and view all the answers

Which of the following is an example of investigator bias in a study?

Determining cause of death based on treatment received (C) Signup and view all the answers

What is a common concern related to loss to follow-up in a study?

>30% loss to follow-up (D) Signup and view all the answers

What is the purpose of keeping study participants engaged in a study during follow-up?

To avoid loss to follow-up (D) Signup and view all the answers

What is the purpose of double-blinding in a study?

Achieve comparability of treated and untreated subjects (C) Signup and view all the answers

Why is random allocation important in a study?

b and c (D) Signup and view all the answers

What is the purpose of standardized procedures in evaluating outcomes?

To avoid biases in outcome assessment (A) Signup and view all the answers

Which bias does double blinding aim to avoid?

Investigator bias (C) Signup and view all the answers

Which type of RCT focuses on keeping healthy people free of disease?

Preventive RCTs (A) Signup and view all the answers

In an Efficacy trial, how are the treatment groups compared?

By comparing those who received the full treatment course (A) Signup and view all the answers

What is a key factor to consider in ensuring compliance in an RCT?

Frequent contact with participants (A) Signup and view all the answers

Why are Effectiveness trials also known as Intent-to-treat analyses?

Because they compare those assigned treatment vs. those who actually complete it (D) Signup and view all the answers

Which situation would be considered an example of Community RCT?

Assessing the impact of water fluoridation on dental caries in two towns (B) Signup and view all the answers

What distinguishes Efficacy trials from Effectiveness trials in terms of group comparison?

Effectiveness trials compare based on intent-to-treat analyses, while Efficacy trials compare based on compliance. (A) Signup and view all the answers

What is a key advantage of Randomized Control Trials (RCTs) highlighted in the text?

Uniform collection of data (A) Signup and view all the answers

Which characteristic is NOT a disadvantage of Randomized Control Trials (RCTs) as mentioned in the text?

Random allocation (A) Signup and view all the answers

What differentiates Quasi-Experimental Study Designs from Randomized Control Trials (RCTs) according to the text?

Randomization (D) Signup and view all the answers

Which type of study design is described as 'Almost experimental' in the text?

Quasi-experimental study (C) Signup and view all the answers

What type of experiments usually involve policy changes or programmatic interventions as noted in the text?

Natural experiments (C) Signup and view all the answers

In which field are Quasi-Experimental Study Designs extensively used as mentioned in the text?

Social sciences (B) Signup and view all the answers

What type of error involves failing to observe a difference between groups when there is actually a difference?

Type 2 Error (B) Signup and view all the answers

Which of the following is a source of bias related to problems in enrollment, loss to follow-up, and poor data collection?

Selection Bias (B) Signup and view all the answers

What is the definition of bias as described in the text?

Mistaken estimate of an exposure's effect on disease (C) Signup and view all the answers

Which of the following is NOT mentioned as a type of bias in the text?

Random Error (C) Signup and view all the answers

What type of error involves observing a difference between groups when there is actually none?

Type 1 Error (C) Signup and view all the answers

What type of error can occur due to incorrect information obtained on variables measured in a study?

Measurement error (D) Signup and view all the answers

How can selection bias be prevented in a study involving cases and controls?

Maintaining careful attention to sampling and sample retention (A) Signup and view all the answers

What is a key strategy to prevent information bias related to the measurement of exposure or disease?

Standardizing measurements and instruments (B) Signup and view all the answers

In what kind of studies is it preferable to have incident cases, clearly defined populations, and prospectively measured exposures?

Prospective studies (B) Signup and view all the answers

What is a method to avoid observer bias in a study protocol according to the text?

Blinding both the investigator and participant (B) Signup and view all the answers

Why is it essential to ensure equal chance for disease detection among exposed and unexposed groups?

To avoid introducing bias towards one group (B) Signup and view all the answers

What is the primary role of a confounder in an epidemiological study?

To distort the true association between exposure and outcome (D) Signup and view all the answers

How is a confounder different from a confounding variable in epidemiological research?

A confounder is always a causal variable, while a confounding variable may not be causal. (A) Signup and view all the answers

When assessing a potential confounder, what is one way to determine if it is associated with the exposure?

Calculate an odds ratio or risk ratio between exposure and confounder. (A) Signup and view all the answers

What is the purpose of determining if a potential confounder is on the causal pathway between exposure and outcome?

To understand the mechanism through which the exposure leads to the outcome (C) Signup and view all the answers

In epidemiological research, why should a non-causal association between an exposure and an outcome be carefully examined?

To identify potential confounders that may distort results (B) Signup and view all the answers

Which of the following statements regarding confounding in epidemiological studies is accurate?

Confounding can lead to incorrect conclusions about causal relationships. (D) Signup and view all the answers

What is the purpose of hypothesis testing in a research study?

To determine if the results reflect the truth (B) Signup and view all the answers

In the context of breast feeding and gastroenteritis among infants, what does the Null Hypothesis (H0) state?

There is no association between breast feeding and gastroenteritis (C) Signup and view all the answers

What is the role of the Alternate Hypothesis (HA) in hypothesis testing?

It suggests a negative association between variables (A) Signup and view all the answers

Why is it important to have a Null Hypothesis (H0) in hypothesis testing?

To establish there is no association between variables (D) Signup and view all the answers

What does hypothesis testing help researchers determine in a study involving breast feeding and gastroenteritis?

The likelihood of random error influencing the results (A) Signup and view all the answers

What is the purpose of confidence intervals in statistics?

To quantify sampling variability around a point estimate (A) Signup and view all the answers

In the context of confidence intervals, what does it mean if the 95% CI includes the null value?

The result is not statistically significant (D) Signup and view all the answers

How is a confidence interval interpreted when it excludes the null value?

The result is statistically significant (B) Signup and view all the answers

What does it mean if a 95% CI for a measure of association is very wide?

The study sample size is small (C) Signup and view all the answers

If a study reports an RR of 1.0 with a 95% CI of 0.8-1.2, what can be concluded?

There is no association between exposure and outcome (B) Signup and view all the answers

Why is it important to understand confidence intervals in epidemiological research?

To capture the precision of estimates and account for sampling variability (D) Signup and view all the answers