Screening tool
The optimal cut off value for the model positivity criterion was
determined by comparison of test classification measures (sensitivity,
specificity, positive predictive value (PPV), negative predictive value
(NPV)) at different cut off values. We prioritized PPV and specificity
over NPV and sensitivity, in order to minimize the number of women that
are erroneously classified as having an adequate intake. A positive test
result indicated an adequate calcium intake.
Finally, we combined the probability scores resulting from the
prediction model into a risk assessment table with corresponding
predictors and their intake frequency ranges. Risk scores were color
coded for high (red), medium (orange) and low (green) probabilities of
having an inadequate calcium intake.