Certified Midwife Exam Prep Research & Evidence-Based Practice 4 — Questions and Answers
Question 1: A midwife reads a case-control study examining risk factors for placental abruption. What is the defining feature of this design?
- Participants are followed forward from exposure to outcome
- Participants are selected based on having the outcome and compared to those without it (Correct answer)
- Participants are randomly assigned to exposure groups
- Prevalence of the condition is measured at a single point in time
Correct answer: Participants are selected based on having the outcome and compared to those without it
Case-control studies start with people who have the outcome (cases) and those who do not (controls), then look backward to compare exposures.
Question 2: Which level of evidence in the GRADE system is assigned when further research is very likely to change confidence in the estimate of effect?
- High
- Moderate
- Low (Correct answer)
- Very Low
Correct answer: Low
GRADE 'Low' quality evidence means further research is very likely to have an important impact on confidence in the effect estimate and may change it.
Question 3: Which statistical measure is MOST useful for understanding the clinical significance of a finding, as opposed to just its statistical significance?
- P-value
- Confidence interval width
- Effect size (e.g., Cohen's d) (Correct answer)
- Chi-square statistic
Correct answer: Effect size (e.g., Cohen's d)
Effect size quantifies the magnitude of a difference or relationship, providing clinical meaning beyond the binary significant/not significant distinction of p-values.
Question 4: During a journal club, a midwife identifies that participants and researchers in a pain management RCT were not blinded. What type of bias is MOST likely introduced?
- Attrition bias
- Detection bias and performance bias (Correct answer)
- Reporting bias
- Confounding bias
Correct answer: Detection bias and performance bias
Lack of blinding of participants causes performance bias (altered behavior), and lack of blinding of outcome assessors causes detection bias (differential outcome measurement).
Question 5: A hospital wants to implement kangaroo mother care based on evidence. Using the Iowa Model of EBP, what is the FIRST step?
- Pilot the practice change on one unit
- Identify a problem-focused or knowledge-focused trigger (Correct answer)
- Assemble a team to review the evidence
- Disseminate the results to staff
Correct answer: Identify a problem-focused or knowledge-focused trigger
The Iowa Model begins with identifying a trigger—either a clinical problem or new knowledge—that prompts the EBP process.
Question 6: A researcher reports absolute risk reduction (ARR) of 2% for postpartum hemorrhage with active management of the third stage. What additional statistic would BEST communicate clinical utility?
- Relative risk reduction (RRR)
- Number needed to treat (NNT) (Correct answer)
- Odds ratio (OR)
- Confidence interval (CI)
Correct answer: Number needed to treat (NNT)
NNT = 1/ARR = 50, meaning 50 women must receive active management to prevent one case of PPH, directly communicating clinical utility.
Question 7: Which research design generates the STRONGEST evidence when evaluating whether a new midwifery intervention reduces cesarean rates?
- Descriptive survey
- Before-and-after study
- Randomized controlled trial (Correct answer)
- Case series
Correct answer: Randomized controlled trial
The RCT, with randomization and control groups, provides the strongest evidence for causality between an intervention and its outcomes.
Certified Midwife Exam Prep Research & Evidence-Based Practice 4
A midwife reads a case-control study examining risk factors for placental abruption.
What is the defining feature of this design?