Research Methods Exam 3

Which regression method is most appropriate when the dependent variable is continuous and you want to adjust for covariates?

Multiple Linear Regression

Which term refers to a variable that is related to both exposure and outcome and can bias an observed association if not controlled?

Confounding variable

Which study design starts with individuals based on exposure and follows forward to observe disease development?

Prospective Cohort Study

In a case-control study, the term ‘controls’ refers to individuals who:

do not have the disease but are similar to the cases

In a simple linear regression, what does the unstandardized coefficient (B) represent?

The change in the dependent variable for every one-unit change in the independent variable

Relative risk (RR) greater than 1 indicates which of the following about the exposure?

Increased risk of the outcome

Recall bias is a limitation in which type of epidemiological study?

Case-control study

In a case-control study, which measure is typically used to quantify the association between exposure and disease?

Odds ratio

Which statement correctly describes the relationship between an odds ratio and the confidence interval (CI) when the CI includes 1.0?

The OR is not likely to be statistically significant

If a dependent variable is continuous, ______________  is the correct type of regression analysis to use.

linear regression

Mean difference in a meta-analysis is most appropriate when:

All included studies measure the outcome on the same scale

What does inverse-variance weighting in meta-analysis give more weight to?

Individual studies with larger sample sizes

What metric is commonly used to express binary outcomes in meta-analysis?

Risk ratio or odds ratio

In a forest plot, what does a diamond representing the summary estimate indicate when it overlaps the vertical line?

The overall effect is not statistically significant

Which meta-analysis effect size would you use to combine continuous outcomes measured on different scales?

Standardized mean difference

Which type of review is most susceptible to selection bias due to lack of a systematic process?

Narrative review

Which statement best describes a meta-analysis that improves precision by pooling data from multiple studies?

It provides a more robust estimate of the treatment effect

What is the primary purpose of a scoping review in nutrition research?

To map the existing literature and identify gaps for future research

Which component of a systematic review uses quantitative methods to combine results from individual studies?

Meta-analysis

Which type of review is primarily designed to answer a specific clinical question by identifying, appraising, and synthesizing all relevant studies using a pre-defined protocol?

Systematic review

What is the implication if the confidence interval of a pooled effect crosses the line of no effect in a forest plot?

The overall effect is not statistically significant

What does a forest plot typically illustrate in a meta-analysis?

Individual study effect estimates and a pooled summary estimate

When studies measure the same outcome with different scales, which effect size is appropriate?

Standardized mean difference (SMD)

In meta-analysis, what is the primary purpose of calculating an effect size?

To quantify the magnitude of the intervention’s effect across studies

What is a key component of allocation concealment in randomized trials?

Ensuring assignment to groups is hidden from researchers enrolling participants

What is the difference between mean difference (MD) and standardized mean difference (SMD)?

MD uses the same scale across studies; SMD standardizes different scales to a common unit

Which domain evaluates how attrition and exclusions might affect study results?

Risk of bias caused by missing outcome data

Which effect size is used when continuous outcomes are measured on the same scale across studies?

Mean difference (MD)

Which type of evidence synthesis combines qualitative and quantitative findings within a single review?

Mixed methods systematic review

Which type of review would be most appropriate for mapping literature and identifying gaps without providing practice guidelines?

Scoping review

In a systematic review, what does the PICO framework help define?

Participants, Intervention, Comparison, Outcome

What is the role of inclusion and exclusion criteria in a systematic review?

To determine which studies will be eligible to address the review question

What is the main function of a meta-analysis within a systematic review?

Provide a quantitative summary by statistically combining results of individual studies

Which type of review is most prone to selection bias due to lack of a systematic, predefined process?

Narrative (literature) review

Which statement best describes a systematic review?

Identifies, appraises, and synthesizes all relevant studies on a specific topic using a pre-defined protocol

What is the purpose of assessing risk of bias in included studies?

To evaluate the methodological quality and potential influence on findings

Which statement best differentiates a narrative review from a systematic review?

Narrative reviews lack a formal, reproducible search and study selection process

Which component of a systematic review protocol ensures reproducibility across researchers?

A pre-defined search strategy and study selection criteria

What is the primary purpose of a scoping review?

Map the existing literature and identify gaps for future research

Which statement describes a simple linear regression model correctly?

One independent variable with no covariates; a straight-line relationship between IV and DV

In regression analysis, what does confounding typically do to the estimated association if not controlled?

Distort or bias the observed relationship between the exposure and outcome

In multiple linear regression, what does the model include that simple linear regression does not?

Two or more independent variables (IVs) and covariates

If a regression model reports R-squared = 0.59, what does this mean?

59% of the variance in the dependent variable is explained by the independent variables in the model

What does Pearson’s correlation coefficient (r) measure in epidemiologic data?

The strength and direction of a linear relationship between two variables

What does the regression coefficient (B) represent in unstandardized form?

The expected change in the dependent variable for a one-unit change in the independent variable, holding other variables constant

Which regression method is typically used when the dependent variable is dichotomous (e.g., disease/no disease)?

Logistic regression

What is the interpretation of a standardized regression coefficient (beta)?

It indicates which independent variable has the strongest relative impact on the dependent variable, in standard deviation units

Which scenario illustrates a regression analysis adjusting for a confounder like smoking when examining coffee and BMI?

Including smoking as a covariate to separate its effect from coffee on BMI

Which regression method is typically used for time-to-event data where the outcome is whether an event occurred and when?

Cox proportional hazards regression

Define a confounding variable in regression analysis.

A variable related to both the exposure and the outcome that can distort the observed association

Which are the three primary types of regression analysis commonly used in epidemiology?

Linear regression, logistic regression, and Cox proportional hazards regression

What is a covariate in regression?

A continuous variable not of primary interest but that affects the outcome and is included to improve precision

What is the purpose of including covariates in a regression model?

To control for factors that influence the outcome and isolate the effect of the primary independent variable

In a case-control study, what is the primary direction of inquiry when selecting participants?

Start with disease status (cases and controls) and look back at past exposures

How do confidence intervals relate to interpretation of ORs in case-control studies?

If the CI includes 1.0, the association may not be statistically significant

What data source is commonly used to determine past exposures in case-control studies?

Questionnaires or interviews, often including FFQs

Why is selection bias a major concern in case-control studies?

Choosing controls that are not comparable to cases can distort associations

Which scenario would likely be least susceptible to recall bias in a case-control study?

Exposure assessment based on objective records (e.g., medical records or registries)

Which design compares individuals with the outcome to similar individuals without the outcome based on prior exposure status?

Case-control study

Which of the following is a correct interpretation of a RR = 0.7 for aspirin and heart attack incidence over 5 years?

The exposure (daily low-dose aspirin) is associated with a 30% reduction in risk of heart attack

Which study design follows a group of individuals over time to observe associations between exposures and disease outcomes, allowing the assessment of incidence?

Cohort study

Which epidemiologic measure compares the incidence of disease among the exposed to the incidence among the non-exposed?

Relative risk (risk ratio)

In a cross-sectional study, what is the primary limitation that weakens causal inference?

Lack of a time dimension between exposure and outcome

Which study design would be most efficient for rare diseases when the exposure is well-documented in records?

Case-control study

Which study design is typically most efficient for studying diseases with long latency periods when exposure data already exist?

Retrospective cohort study

What does a relative risk (RR) of 1.0 indicate in nutritional epidemiology?

No difference in risk between exposed and non-exposed groups

A retrospective cohort study most strongly relies on which of the following data sources?

Existing medical records or databases

Which term describes the total burden of disease or health-related states in a population at a given time?

Prevalence