What two values determine the product of the concordance correlation coefficient?

• A. Bias and prevalence
• B. Accuracy parameter and Pearson correlation coefficient
• C. Sensitivity and specificity
• D. True positive rate and false positive rate

Answer: (B)

Concordance correlation coefficient blends two ideas: precision and accuracy. Precision is captured by the Pearson correlation coefficient, which tells you how well the two measurements track each other linearly. Accuracy is captured by an accuracy parameter (a bias-correction factor) that measures how far the measurements are from the identity line, reflecting systematic differences between the methods. The CCC is the product of these two components, so the two values that determine it are the accuracy parameter and the Pearson correlation coefficient. A high CCC requires both strong correlation and little bias, meaning the methods agree closely across the range of values. The other options describe diagnostic test performance or prevalence, not the two components that define the CCC.