DRC Research Methods & Evidence-Based Practice 3 — Questions and Answers
Question 1: Which statistical measure indicates the proportion of true-positive results among all patients who actually have the disease in a radiographic diagnostic test?
- Specificity
- Positive predictive value
- Sensitivity (Correct answer)
- Negative predictive value
Correct answer: Sensitivity
Sensitivity measures the ability of a test to correctly identify those who have the disease (true-positive rate).
Question 2: A dental hygiene researcher wants to compare caries detection rates on periapical films versus CBCT in patients aged 18–65. What is the MOST appropriate study design?
- Case report
- Ecological study
- Randomized controlled trial (Correct answer)
- Case series
Correct answer: Randomized controlled trial
An RCT with random assignment to imaging modality provides the highest-level evidence for comparing two diagnostic interventions.
Question 3: Inter-rater reliability in radiographic interpretation studies is BEST measured by:
- Pearson correlation coefficient
- Cohen's kappa statistic (Correct answer)
- Odds ratio
- Number needed to treat
Correct answer: Cohen's kappa statistic
Cohen's kappa statistic measures the level of agreement between two raters beyond what would be expected by chance.
Question 4: In evidence-based dental radiology, a Level I evidence source would MOST likely be a:
- Single case report describing a rare periapical lesion
- Cross-sectional survey of radiographic practices
- Systematic review or meta-analysis of RCTs (Correct answer)
- Expert committee opinion
Correct answer: Systematic review or meta-analysis of RCTs
Systematic reviews and meta-analyses of well-designed RCTs represent the highest level (Level I) of evidence in most hierarchies.
Question 5: A study reports an odds ratio (OR) of 1.0 for caries development between annual and biennial bitewing schedules. This result MOST accurately means:
- Annual radiographs double the caries detection rate
- There is no difference in odds of caries between the two schedules (Correct answer)
- Biennial radiographs are superior for caries detection
- The study lacked statistical power
Correct answer: There is no difference in odds of caries between the two schedules
An OR of 1.0 indicates equal odds in both groups, meaning no association was detected between radiograph frequency and caries development.
Question 6: Which of the following BEST describes a cross-sectional study design in dental radiology research?
- Patients are randomly assigned to radiographic versus no radiographic examination
- Data on exposure and outcome are collected at the same point in time (Correct answer)
- A group with disease is matched to a group without disease and exposures are compared
- Participants are followed prospectively for several years
Correct answer: Data on exposure and outcome are collected at the same point in time
Cross-sectional studies capture exposure and outcome data simultaneously from a population at a single time point, providing a 'snapshot.'
Question 7: A dental hygiene program wants to implement EBP guidelines for radiographic selection. The FIRST step in translating evidence into clinical practice is:
- Purchasing new digital radiography equipment
- Identifying a clinical question and searching for best evidence (Correct answer)
- Training staff on new imaging software
- Auditing existing patient radiographic records
Correct answer: Identifying a clinical question and searching for best evidence
EBP always begins with formulating a clinical question and then searching for the best available evidence to answer it.
DRC Research Methods & Evidence-Based Practice 3
Which statistical measure indicates the proportion of true-positive results among all patients who actually have the disease in a radiographic diagnostic test?