NBCE Research and Development 4

Question 1

Inter-rater reliability is best assessed using which statistical measure for categorical outcomes?

Accepted Answer

Cohen's kappa

Answer

Pearson correlation coefficient

Answer

Intraclass correlation coefficient

Answer

Cronbach's alpha

Question 2

The number needed to treat (NNT) represents:

Accepted Answer

The number of patients who must receive a treatment for one additional patient to benefit

Answer

The average number of treatments required per patient visit

Answer

The minimum sample size required to achieve statistical significance

Answer

The cost-effectiveness ratio per unit of clinical improvement

Question 3

In a prospective cohort study examining chiropractic care and headache frequency, the exposure is measured:

Accepted Answer

Before the outcome develops, as participants are followed forward in time

Answer

After the outcome has already occurred

Answer

At the same time the outcome is assessed

Answer

Retrospectively from existing medical records

Question 4

Which statement best describes content validity of a chiropractic patient outcome questionnaire?

Accepted Answer

Test items comprehensively represent all relevant domains of the construct being measured

Answer

The questionnaire produces consistent scores over repeated administrations

Answer

Scores on the questionnaire correlate strongly with a well-established gold standard measure

Answer

The questionnaire successfully predicts future patient functional status

Question 5

Confounding in an observational study occurs when:

Accepted Answer

A third variable is associated with both the exposure and the outcome

Answer

Participants are lost to follow-up at different rates between groups

Answer

Measurement error affects the accuracy of outcome recording

Answer

The study population differs substantially from the target population

Question 6

A researcher reports a 95% confidence interval of 2.1 to 4.7 for a relative risk estimate. This means:

Accepted Answer

If the study were repeated 100 times, approximately 95 intervals would contain the true value

Answer

There is a 95% probability the true relative risk falls in this range

Answer

The study has 95% statistical power to detect this effect

Answer

The p-value for this result is exactly 0.05

Question 7

In outcomes research, the minimal clinically important difference (MCID) refers to:

Accepted Answer

The minimum change in a patient-reported outcome considered meaningful to the patient

Answer

The smallest effect detectable by the statistical test used

Answer

The threshold at which statistical significance is achieved in the sample

Answer

The maximum acceptable difference between groups in a non-inferiority trial