What does it mean when a pair of primary and secondary cases is correctly ordered?

When a pair of primary and secondary cases is correctly ordered, it indicates that there is a concordance between the two cases. In statistical terms, concordance refers to the situation where two instances (in this case, the primary and secondary cases) exhibit a consistent and harmonious relationship in their ordering.

For example, if both cases show the same ranking or if one case is greater than the other in the same order, then they are said to be concordant. This concept is central to assessments where the relationship between variables needs to be measured, such as in predictive modeling or when validating models in SAS Enterprise Miner.

The other options represent different concepts that do not align with the idea of correct ordering of pairs. Discordance would imply that the cases show an inconsistent relationship or contradict each other, while independence suggests that the two cases do not influence each other at all. Correlation refers to a statistical measure of how two variables move in relation to each other, which does not specifically imply a correct ordering in the context of primary and secondary cases.