DRC Research Methods & Evidence-Based Practice 2 — Questions and Answers
Question 1: In a systematic review on dental radiographic techniques, which step is performed FIRST?
- Extracting data from selected studies
- Formulating a focused clinical question (Correct answer)
- Conducting a meta-analysis
- Appraising study quality
Correct answer: Formulating a focused clinical question
A focused clinical question (often using PICO format) must be defined before any other step in a systematic review.
Question 2: A dental hygienist reads that a new digital sensor reduces patient dose by 40%. Which parameter is MOST important to evaluate the clinical significance of this finding?
- The journal's impact factor
- The effect size and confidence interval (Correct answer)
- The number of authors on the study
- Whether the study was peer-reviewed
Correct answer: The effect size and confidence interval
Effect size paired with a confidence interval tells the clinician how large and how precise the reported difference actually is.
Question 3: Which type of bias occurs when radiographic studies with positive findings are more likely to be published than those with negative results?
- Selection bias
- Measurement bias
- Publication bias (Correct answer)
- Attrition bias
Correct answer: Publication bias
Publication bias skews the literature toward positive outcomes because negative or null results are less frequently submitted or accepted for publication.
Question 4: A researcher uses a funnel plot to assess a meta-analysis on radiographic caries detection. An asymmetric funnel plot most likely indicates:
- High heterogeneity among included studies
- Publication bias or small-study effects (Correct answer)
- Adequate statistical power
- Homogeneous patient populations
Correct answer: Publication bias or small-study effects
Asymmetry in a funnel plot is a common indicator of publication bias or systematic differences related to study size.
Question 5: When applying EBP to radiographic selection criteria, the term 'external validity' refers to:
- Whether the study measuring instrument was calibrated
- How well study results can be generalized to other patient populations (Correct answer)
- The internal consistency of questionnaire responses
- Whether randomization was properly conducted
Correct answer: How well study results can be generalized to other patient populations
External validity (generalizability) describes how applicable research findings are to patients beyond the specific study sample.
Question 6: A cohort study follows patients who received bitewing radiographs annually versus every 2 years over 10 years. What is the PRIMARY advantage of this design?
- It eliminates confounding variables entirely
- It allows observation of exposure-outcome relationships over time (Correct answer)
- It is less expensive than a cross-sectional study
- It requires no ethical approval
Correct answer: It allows observation of exposure-outcome relationships over time
Cohort studies prospectively (or retrospectively) track defined groups to observe how an exposure relates to outcomes over time.
Question 7: The PICO framework used in EBP stands for Patient/Population, Intervention, Comparison, and:
- Outcome (Correct answer)
- Observation
- Objective
- Oversight
Correct answer: Outcome
The 'O' in PICO stands for Outcome, which specifies what result the clinician wants to measure or achieve.
DRC Research Methods & Evidence-Based Practice 2
In a systematic review on dental radiographic techniques, which step is performed FIRST?