Psychometric Outcome	Description
Cronbach’s alpha	measure of internal consistency, that is, how closely correlated a set of scale items are, as a group.
Kappa	measure of inter-rater agreement or inter-rater reliability for qualitative (categorical) items which takes into account the possibility of the agreement occurring by chance.
Sensitivity	measure of a test/scales’ ability to correctly detect patients who do truly have the condition (i.e., proportion of people who screen positive for substance use disorders according to the scale, among those who truly have substance use disorders based on an established standard (“gold standard”) such as meeting diagnostic criteria for a disorder).
Specificity	measure of the test/scales’ ability to correctly detect patients without a condition (i.e., proportion of people who screen negative for substance use disorders according to the scale, among those who truly do not have substance use disorders based on an established standard such as meeting diagnostic criteria for a disorder).
Positive predictive value (PPV)	the probability that persons with a positive screening result actually has the disorder. (i.e., proportion of people who meet diagnostic criteria for a substance use disorder among those who screened positive for the disorder on a scale).
Negative predictive value (NPV)	the probability that people with a negative screening test actually do not have the disease. (i.e., proportion of people who meet diagnostic criteria for a substance use disorder among those who screened negative for a substance use disorder in a scale).