NP Research & Evidence-Based Practice 4 — Questions and Answers
Question 1: A cohort study follows 500 smokers and 500 non-smokers for 10 years to assess lung cancer incidence. What is the primary advantage of this design over a case-control study?
- It allows direct calculation of incidence rates and relative risk (Correct answer)
- It eliminates recall bias entirely
- It is faster and less expensive to conduct
- It provides stronger evidence than an RCT
Correct answer: It allows direct calculation of incidence rates and relative risk
Prospective cohort studies allow direct measurement of incidence rates and calculation of relative risk because exposure precedes outcome.
Question 2: An NP identifies an I² value of 75% in a meta-analysis. What does this suggest?
- High heterogeneity exists among the included studies (Correct answer)
- The pooled effect estimate is highly reliable
- 75% of studies showed significant results
- The meta-analysis included too few studies
Correct answer: High heterogeneity exists among the included studies
I² quantifies the proportion of variability due to heterogeneity rather than chance; values above 50–75% indicate substantial to considerable heterogeneity.
Question 3: According to the Belmont Report, the principle of beneficence in research requires that investigators:
- Maximize benefits and minimize harms to research participants (Correct answer)
- Ensure equitable selection and distribution of research burdens
- Obtain voluntary informed consent from all participants
- Protect the confidentiality of all participant data
Correct answer: Maximize benefits and minimize harms to research participants
The Belmont principle of beneficence obligates researchers to maximize potential benefits while minimizing potential harms to participants.
Question 4: A patient asks an NP about a new medication with an absolute risk reduction of 2% and a relative risk reduction of 40%. Which statistic is most clinically meaningful to share?
- Absolute risk reduction of 2%, as it reflects the true magnitude of benefit
- Relative risk reduction of 40%, as it better motivates adherence
- Number needed to treat, calculated from the absolute risk reduction (Correct answer)
- Both statistics equally, without prioritizing one over the other
Correct answer: Number needed to treat, calculated from the absolute risk reduction
NNT (1/ARR = 50) is the most clinically actionable statistic, translating absolute risk reduction into a concrete patient-level benefit measure.
Question 5: Which research design uses an iterative cycle of planning, acting, observing, and reflecting to improve clinical practice within a specific setting?
- Action research (Correct answer)
- Grounded theory
- Ethnography
- Phenomenology
Correct answer: Action research
Action research is a participatory, cyclical approach designed to solve practical problems and improve practice within a specific real-world context.
Question 6: An NP evaluates a screening test with sensitivity of 90% and specificity of 85%. In a population with low disease prevalence, which outcome is most likely?
- A high rate of false positives reducing positive predictive value (Correct answer)
- A high rate of false negatives reducing negative predictive value
- The positive predictive value will be high
- Sensitivity and specificity will decrease with lower prevalence
Correct answer: A high rate of false positives reducing positive predictive value
In low-prevalence populations, even highly specific tests generate more false positives than true positives, substantially lowering PPV.
Question 7: Which IRB category applies to research involving anonymous surveys about benign topics such as dietary habits in healthy adults?
- Exempt review (Correct answer)
- Expedited review
- Full board review
- Continuing review
Correct answer: Exempt review
Anonymous surveys on benign topics with minimal risk typically qualify for exempt status under federal regulations (45 CFR 46.104).
NP Research & Evidence-Based Practice 4
A cohort study follows 500 smokers and 500 non-smokers for 10 years to assess lung cancer incidence.
What is the primary advantage of this design over a case-control study?