Slideshow Videos Research & Evidence-Based Practice 2 — Questions and Answers
Question 1: In a randomized controlled trial (RCT), what is the primary purpose of randomization?
- To increase sample size
- To eliminate selection bias (Correct answer)
- To improve blinding of participants
- To reduce attrition rates
Correct answer: To eliminate selection bias
Randomization distributes known and unknown confounders equally across groups, eliminating selection bias.
Question 2: Which level of the evidence hierarchy is typically considered strongest for clinical decision-making?
- Expert opinion
- Case-control studies
- Systematic reviews and meta-analyses (Correct answer)
- Cohort studies
Correct answer: Systematic reviews and meta-analyses
Systematic reviews and meta-analyses pool data from multiple high-quality studies, providing the strongest level of evidence.
Question 3: A researcher wants to study whether a medication causes a rare side effect. Which study design is MOST appropriate?
- Randomized controlled trial
- Case-control study (Correct answer)
- Cross-sectional survey
- Ecological study
Correct answer: Case-control study
Case-control studies are ideal for rare outcomes because they start with cases who have the outcome and compare them to controls.
Question 4: What does a confidence interval (CI) that does NOT cross 1.0 indicate in a relative risk calculation?
- The result is clinically insignificant
- The result is statistically significant (Correct answer)
- The sample size was too small
- There is no difference between groups
Correct answer: The result is statistically significant
A 95% CI for relative risk that excludes 1.0 indicates the association is statistically significant at the p<0.05 level.
Question 5: What is the term for systematic error introduced when study participants are not representative of the target population?
- Confounding
- Selection bias (Correct answer)
- Information bias
- Attrition bias
Correct answer: Selection bias
Selection bias occurs when the sample systematically differs from the population of interest, limiting generalizability.
Question 6: A nurse practitioner reads a study reporting an odds ratio of 2.5. How should this be interpreted?
- The risk in the exposed group is 2.5 times higher
- The exposed group has 2.5 times the odds of the outcome compared to the unexposed (Correct answer)
- The probability of the outcome is 2.5%
- The study found a 2.5% absolute risk reduction
Correct answer: The exposed group has 2.5 times the odds of the outcome compared to the unexposed
An odds ratio of 2.5 means the odds of the outcome in the exposed group are 2.5 times greater than in the unexposed group.
Question 7: Which concept describes the degree to which a research instrument consistently measures what it is intended to measure across repeated trials?
- Validity
- Reliability (Correct answer)
- Sensitivity
- Specificity
Correct answer: Reliability
Reliability refers to the consistency of a measurement tool yielding the same results under the same conditions.
Slideshow Videos Research & Evidence-Based Practice 2
In a randomized controlled trial (RCT), what is the primary purpose of randomization?