Cohort studies are a powerful type of observational research used to investigate the link between exposures and outcomes. While they cannot prove causation with the certainty of a randomized controlled trial, a well-designed cohort study can provide strong evidence about the prognosis, incidence, and etiology of a disease. The ability to critically appraise these studies is a key skill for pharmacists, as taught in courses like Principles of Evidence-Based Practice and applied as a “Transcending Concept” in Patient Care 5. This quiz will test your knowledge on the design, analysis, and critical appraisal of cohort studies.
1. A cohort study is classified as what type of study design?
- a. Experimental
- b. Observational
- c. Case Report
- d. Meta-analysis
Answer: b. Observational
2. What is the defining characteristic of a prospective cohort study?
- a. It starts with a group of patients who already have the disease and looks back in time for exposures.
- b. It assesses exposures and outcomes at a single point in time.
- c. It follows two or more groups (cohorts) forward in time from exposure to outcome.
- d. The researcher randomly assigns the exposure to the participants.
Answer: c. It follows two or more groups (cohorts) forward in time from exposure to outcome.
3. What is the primary measure of association calculated in a cohort study?
- a. Odds Ratio (OR)
- b. Relative Risk (RR)
- c. P-value
- d. Standard Deviation
Answer: b. Relative Risk (RR)
4. A Relative Risk of 2.5 for developing a disease in an exposed group means:
- a. The exposed group is 2.5 times more likely to develop the disease than the unexposed group.
- b. The exposed group has a 2.5% chance of developing the disease.
- c. The exposure is protective against the disease.
- d. The result is not statistically significant.
Answer: a. The exposed group is 2.5 times more likely to develop the disease than the unexposed group.
5. A major strength of a prospective cohort study is its ability to:
- a. Be completed quickly and inexpensively.
- b. Establish temporality (i.e., that the exposure preceded the outcome).
- c. Eliminate all forms of bias.
- d. Prove causation definitively.
Answer: b. Establish temporality (i.e., that the exposure preceded the outcome).
6. The “Review and appraisal of cohort studies” is a specific “Transcending Concept” in which course?
- a. PHA5787C Patient Care 5
- b. PHA5104 Sterile Compounding
- c. PHA5703 Pharmacy Law and Ethics
- d. PHA5784C Patient Care 4
Answer: a. PHA5787C Patient Care 5
7. A researcher identifies a group of patients with a rare disease and a group without the disease, then looks back at their past medication use. This is a:
- a. Cohort study
- b. Case-control study
- c. Randomized controlled trial
- d. Cross-sectional study
Answer: b. Case-control study
8. What is the main disadvantage of a prospective cohort study design?
- a. It is not good for studying rare exposures.
- b. It is prone to recall bias.
- c. It can be very time-consuming and expensive, and is inefficient for studying rare diseases.
- d. It cannot calculate incidence.
Answer: c. It can be very time-consuming and expensive, and is inefficient for studying rare diseases.
9. A third variable that is associated with both the exposure and the outcome, and which can distort the true relationship between them, is known as a(n):
- a. Odds ratio
- b. Confounding variable
- c. P-value
- d. Relative risk
Answer: b. Confounding variable
10. When critically appraising a cohort study, what is one of the first questions you should ask about its validity?
- a. Was the p-value less than 0.05?
- b. Did the study have a clear and focused research question?
- c. Was the study published in a high-impact journal?
- d. Did the authors use a t-test?
Answer: b. Did the study have a clear and focused research question?
11. The appraisal of cohort studies is a specific lecture within the Principles of Evidence-Based Practice course.
- a. True
- b. False
Answer: a. True
12. Loss to follow-up in a cohort study can lead to what type of bias?
- a. Selection bias
- b. Attrition bias
- c. Recall bias
- d. Interviewer bias
Answer: b. Attrition bias
13. A Relative Risk of 1.0 indicates that:
- a. The exposure is a strong risk factor for the outcome.
- b. The exposure is strongly protective against the outcome.
- c. There is no association between the exposure and the outcome.
- d. The study results are invalid.
Answer: c. There is no association between the exposure and the outcome.
14. A 95% Confidence Interval for a Relative Risk is reported as (1.2 – 3.4). This result is:
- a. Not statistically significant because the interval is too wide.
- b. Not statistically significant because it includes 1.0.
- c. Statistically significant because the entire interval is above 1.0.
- d. Clinically insignificant.
Answer: c. Statistically significant because the entire interval is above 1.0.
15. A 95% Confidence Interval for a Relative Risk is reported as (0.8 – 2.1). This result is:
- a. Statistically significant because the effect could be harmful.
- b. Statistically significant because the effect could be protective.
- c. Not statistically significant because the interval crosses 1.0.
- d. Both statistically and clinically significant.
Answer: c. Not statistically significant because the interval crosses 1.0.
16. Cohort studies are a type of observational study.
- a. True
- b. False
Answer: a. True
17. “Internal validity” of a study refers to:
- a. The degree to which the study results can be generalized to other populations.
- b. The statistical power of the study.
- c. The degree to which the study is free from bias and confounding, and the results are trustworthy for the study population.
- d. The journal in which the study was published.
Answer: c. The degree to which the study is free from bias and confounding, and the results are trustworthy for the study population.
18. Which study design is considered the “gold standard” for determining the efficacy of a new therapeutic intervention?
- a. Cohort study
- b. Case-control study
- c. Randomized controlled trial
- d. Case report
Answer: c. Randomized controlled trial
19. A key difference between a retrospective cohort study and a case-control study is:
- a. A retrospective cohort study starts with an exposure and looks forward to an outcome, while a case-control study starts with an outcome and looks back for an exposure.
- b. A case-control study is always prospective.
- c. A retrospective cohort study is experimental.
- d. There is no difference.
Answer: a. A retrospective cohort study starts with an exposure and looks forward to an outcome, while a case-control study starts with an outcome and looks back for an exposure.
20. An active learning session on appraising cohort studies is part of the Patient Care 5 course.
- a. True
- b. False
Answer: a. True
21. In a cohort study examining the link between a new medication and a specific adverse event, the “exposure” is:
- a. The adverse event.
- b. The use of the new medication.
- c. The patient’s age.
- d. The duration of the study.
Answer: b. The use of the new medication.
22. How can researchers control for confounding variables in the analysis phase of a cohort study?
- a. By using randomization.
- b. By using blinding.
- c. By using statistical adjustment methods like stratification or multivariable regression.
- d. It is not possible to control for confounding variables.
Answer: c. By using statistical adjustment methods like stratification or multivariable regression.
23. “Recall bias” is a major concern in which type of study design?
- a. Randomized controlled trials
- b. Prospective cohort studies
- c. Retrospective studies like case-control studies
- d. All study designs equally.
Answer: c. Retrospective studies like case-control studies
24. An active learning session on EBP is part of which course?
- a. PHA5787C Patient Care 5
- b. PHA5163L Professional Skills Lab 3
- c. PHA5781 Patient Care I
- d. PHA5782C Patient Care 2
Answer: a. PHA5787C Patient Care 5
25. A Relative Risk of 0.7 indicates that:
- a. The exposure increases the risk of the outcome by 70%.
- b. The exposure increases the risk of the outcome by 30%.
- c. The exposure decreases the risk of the outcome by 30%.
- d. The exposure decreases the risk of the outcome by 70%.
Answer: c. The exposure decreases the risk of the outcome by 30%.
26. The “Results” section of a research paper should primarily contain:
- a. The authors’ interpretation and opinions.
- b. A review of prior literature.
- c. A neutral, factual presentation of the study’s data and findings.
- d. A detailed description of the study methods.
Answer: c. A neutral, factual presentation of the study’s data and findings.
27. “External validity” refers to:
- a. The trustworthiness of the results for the study participants.
- b. The generalizability of the study results to a broader patient population.
- c. The statistical significance of the findings.
- d. The internal consistency of the measurements.
Answer: b. The generalizability of the study results to a broader patient population.
28. An active learning session on appraising cohort studies is part of which course module?
- a. Module 5: Urological Disorders
- b. Module 1: Diabetes Mellitus
- c. Module 4: Medication Safety
- d. Module 8: Men’s Health
Answer: a. Module 5: Urological Disorders
29. When appraising a cohort study, it is important to assess whether the outcome was measured:
- a. In the same way for both the exposed and unexposed groups.
- b. Only in the exposed group.
- c. Only in the unexposed group.
- d. By the participants themselves without verification.
Answer: a. In the same way for both the exposed and unexposed groups.
30. The “Journal Club” is an activity where students practice appraising primary literature.
- a. True
- b. False
Answer: a. True
31. In a cohort study, the unexposed group is often referred to as the:
- a. Placebo group
- b. Control or comparison group
- c. Case group
- d. Intervention group
Answer: b. Control or comparison group
32. The ability to calculate and interpret measures like Relative Risk is a key objective of the EBP course.
- a. True
- b. False
Answer: a. True
33. The “Discussion” section of a research paper is where the authors should:
- a. Present their data for the first time.
- b. Describe how their results compare to other studies and discuss the study’s limitations.
- c. State the research question.
- d. Detail the statistical analysis plan.
Answer: b. Describe how their results compare to other studies and discuss the study’s limitations.
34. Cohort studies are particularly well-suited for studying:
- a. The outcomes of rare exposures.
- b. The prevalence of a disease.
- c. The efficacy of a new drug.
- d. Rare diseases.
Answer: a. The outcomes of rare exposures.
35. A pharmacist reading a cohort study should ask if the study population is similar to their own patient population before applying the results. This relates to the concept of:
- a. Internal validity
- b. Statistical significance
- c. External validity or applicability
- d. Confounding
Answer: c. External validity or applicability
36. The “Methods” section of a study should be detailed enough to allow another researcher to:
- a. Replicate the study.
- b. Understand the authors’ conclusions.
- c. See the raw data.
- d. Determine the clinical significance.
Answer: a. Replicate the study.
37. Which of the following is NOT a type of bias in observational studies?
- a. Selection bias
- b. Information bias
- c. Recall bias
- d. Randomization
Answer: d. Randomization
38. The reading for the module on cohort studies is an article about androgen deprivation therapy and dementia risk.
- a. True
- b. False
Answer: a. True
39. A key question when appraising the follow-up in a cohort study is:
- a. Was the follow-up long enough for the outcome to occur?
- b. Was the follow-up complete (i.e., were few subjects lost)?
- c. Both a and b.
- d. Neither a nor b.
Answer: c. Both a and b.
40. An active learning session covering EBP is part of which course?
- a. PHA5787C Patient Care 5
- b. PHA5163L Professional Skills Lab 3
- c. PHA5781 Patient Care I
- d. PHA5782C Patient Care 2
Answer: a. PHA5787C Patient Care 5
41. The term “inception cohort” means that:
- a. All subjects were at a similar, early point in the course of their exposure.
- b. The study was conducted at the inception of a new hospital.
- c. All subjects had the outcome at the beginning of the study.
- d. The study had major design flaws from its inception.
Answer: a. All subjects were at a similar, early point in the course of their exposure.
42. A cohort study can be either prospective or retrospective.
- a. True
- b. False
Answer: a. True
43. The primary difference between a cohort study and an RCT is the lack of _____ in a cohort study.
- a. a comparison group
- b. a defined outcome
- c. randomization
- d. statistical analysis
Answer: c. randomization
44. A pharmacist must be able to appraise a cohort study to:
- a. Understand the evidence behind a guideline recommendation.
- b. Answer a drug information question about the risk of an adverse effect.
- c. Make an informed decision when other, higher levels of evidence are not available.
- d. All of the above.
Answer: d. All of the above.
45. If a cohort study shows an association between an exposure and an outcome, it proves that the exposure caused the outcome.
- a. True
- b. False
Answer: b. False
46. Which of the following is an example of confounding? A study finds that coffee drinking (exposure) is associated with lung cancer (outcome). However, smokers are more likely to drink coffee, and smoking causes lung cancer. In this case, ____ is the confounder.
- a. Coffee drinking
- b. Lung cancer
- c. Smoking
- d. The study design
Answer: c. Smoking
47. “Observational Studies” is a module in the Principles of Evidence-Based Practice course.
- a. True
- b. False
Answer: a. True
48. An active learning session on cohort studies is part of which course?
- a. PHA5787C Patient Care 5
- b. PHA5163L Professional Skills Lab 3
- c. PHA5781 Patient Care I
- d. PHA5782C Patient Care 2
Answer: a. PHA5787C Patient Care 5
49. The overall goal of critically appraising any study is to:
- a. Find flaws in the authors’ work.
- b. Determine if the results are valid and applicable to your patient care decisions.
- c. Memorize the p-value.
- d. Publish a letter to the editor.
Answer: b. Determine if the results are valid and applicable to your patient care decisions.
50. The ultimate reason to learn how to appraise cohort studies is to:
- a. Be able to use the best available evidence to provide optimal patient care.
- b. Pass the EBP final exam.
- c. Impress your preceptors.
- d. Become a clinical researcher.
Answer: a. Be able to use the best available evidence to provide optimal patient care.