Interpreting Measures of Association

In the context of interpreting measures of association, what does a value greater than 1 indicate?

What does a measure of association equal to 1 imply?

What type of relationship is indicated by a measure of association less than 1?

Which of the following is NOT a potential reason for the results observed in a study?

What does 'internal validity' primarily assess in a research study?

What aspect of a research study does 'external validity' address?

A study shows a strong association between two variables, but the researchers suspect that a third, unmeasured variable is influencing both. What threat to validity are they most concerned about?

A researcher designs a study with rigorous controls and standardized procedures. What aspect of the study is the researcher primarily trying to maximize?

Which of the following best describes the concept of confounding in epidemiological studies?

A variable is considered a confounder when it meets which of the following criteria?

In a study examining the relationship between coffee consumption and lung cancer, smoking is suspected as a confounder. What does this suggest?

Based on the data provided, what is the relative risk (RR) of lung cancer for individuals who drink coffee compared to those who do not?

Why is it important to address confounding in epidemiological studies?

Which of the following is NOT a characteristic of a confounding variable?

In the context of the 'Big Picture' of epidemiology presented, how does a confounder affect the relationship between exposure and outcome?

If a study finds a strong association between two variables, but fails to account for a known confounder, what is the likely consequence?

Based on the information provided, what is the most likely relationship between coffee consumption and lung cancer, considering smoking status?

Why is it important to stratify the data by smoking status when studying the association between coffee and lung cancer?

If the adjusted association between coffee and lung cancer (after accounting for smoking) is substantially different from the unadjusted association, what does this suggest?

In the context of this study, what would be the most effective strategy to address the potential confounding effect of smoking?

Given the data provided, if the relative risk of lung cancer for coffee drinkers compared to non-coffee drinkers is 1.83 overall, but 1.00 within both smokers and non-smokers, this indicates that:

Based on the provided information, what condition must be met for smoking to be considered a confounder in the relationship between coffee consumption and lung cancer?

Using the provided criteria RR1 < ALL RR > RR2 or RR1 > ALL RR < RR2, determine if confounding is present.

Which of the following study designs would be most effective in minimizing the potential for confounding by smoking when investigating the relationship between coffee consumption and lung cancer?

Which of the following best describes bias in research?

In a study examining the association between a new drug and a specific health outcome, researchers find a relative risk of 1.5. If the true relative risk is 1.8, which type of bias is most likely present?

A study investigating the effect of exercise on weight loss reports an odds ratio of 0.6. However, the actual odds ratio is 0.8. Which of the following describes the direction of bias?

A researcher aims to study the association between smoking and lung cancer. However, the participants are selected in a way that those with early-stage lung cancer are more likely to be included. How could this affect the study?

In a clinical trial, participants who are given a new medication are more closely monitored for side effects than those receiving the placebo. How might this difference in follow-up affect the study results?

Which of the following scenarios would most likely result in bias toward the null?

Researchers are studying the effectiveness of a new educational program. They suspect that more motivated students are more likely to enroll in the program. How could this enrolment bias affect the study?

A study aims to determine the association between a dietary supplement and cardiovascular health, but the researchers are selectively publishing only the positive results. What type of bias is most likely to be introduced?

In a randomized controlled trial (RCT), what is the primary purpose of randomization?

Why are observational studies generally more susceptible to confounding than experimental studies?

In the context of epidemiologic studies, what is the most significant advantage of randomization in experimental studies like RCTs?

Given a 2x2 table from a cohort study on coffee consumption and gout, what does the 'unadjusted RR' represent?

In a hypothetical study examining the relationship between coffee consumption and the incidence of gout, the following data is observed:

• High Coffee: Gout = 42, No Gout = 22,765
• No Coffee: Gout = 143, No Gout = 20,530

Calculate the unadjusted Relative Risk (RR) for developing gout among those with high coffee consumption compared to those with no coffee consumption.

Using the RR calculated previously (0.27) for the association between coffee consumption and gout, what is the percentage decrease in the risk of gout associated with high coffee consumption?

What does a percentage decrease of 73% calculated from an unadjusted RR of 0.27 in a study of coffee consumption and gout suggest, before considering further analysis?

If age is a confounder in the relationship between coffee consumption and gout, what does this imply?

In a study examining the association between exercise and cardiovascular health, researchers only include participants who are already highly motivated to exercise. What type of bias is most likely to be introduced?

A study aims to determine the effectiveness of a new drug. Participants in the treatment group are more likely to report positive outcomes due to increased attention from the study staff. This scenario exemplifies which type of bias?

If a direct association is biased towards the null, how is the true association affected?

A study finds a biased measure of association is 0.3, while the true measure of association is 0.6. What type of bias and direction does this represent?

A study investigating the impact of a new educational program relies on self-reported data from students, but students who feel they have not benefited from the program are less likely to respond. What type of bias is most concerning in this scenario?

In a clinical trial for a new pain medication, researchers suspect that the patients' belief in the medication's effectiveness is influencing their reported pain levels. If this belief leads to an overestimation of the drug's effect, which type of bias is most likely at play?

In a study assessing the relationship between smoking and lung cancer, researchers only include data from participants who have been diagnosed with lung cancer within the past year. What type of bias might be introduced?

A researcher is conducting a study on the effects of a new drug on blood pressure. They unconsciously tend to record slightly lower blood pressure readings for patients in the treatment group compared to the control group. What type of bias is most likely occurring?

Confounding

Confounder

Confounding (Phenomenon)

Exposure

Outcome

Exposure to Outcome

Confounder Criteria

Relative Risk (RR)

Measure of Association > 1

Measure of Association = 1

Measure of Association < 1

Real Study Result

Study Result Due to Chance

Confounded Study Result

Biased Study Result

Internal Validity

Randomization

Goal of Randomization

Benefit of Randomization

Observational Studies

Vulnerability to Confounding

Unadjusted RR

Incidence Calculation

Stratum-specific effect

Stratum-specific Relative Risk (RR)

All RR (Crude RR)

Confounding Indication

Confounding Presence

Confounder Example

Why Smoking is a Confounder

Bias (Definition)

Bias Occurrences

Bias Away From Null

Bias Towards Null

Inverse Bias

Bias Towards the Null (Example)

Towards the Null

Direct Bias

Bias (in a study)

Bias towards the null

Bias away from the null

Direct association, away from the null

Direct association, towards the null

Inverse association, away from the null

Inverse association, towards the null

Selection Bias

Information Bias