Transition Probabilities

The OUD model is clinically complex, and it requires a large number of estimates of the probabilities of transitioning from one state to another (e.g., risk of a non-user developing OUD, or the risk of a person with OUD experiencing an opioid overdose). Given the complexity of the model, there are nearly 100 parameters that must be estimated from the literature and finalized by calibration.

Transition probabilities govern how individuals transition between clinical states represented in the model. These transition probabilities are complex, and are dependent upon a series of individual characteristics (age, gender, race, income, mental health diagnoses, polysubstance use, etc.) Therefore, several of the transition probabilities are represented as logistic regression equations, which include coefficients for each of these individual characteristics.


Probability of staying in the same state calculated as (1 - probability of transition to other states)
Structural zeros (no transition)
The transition is assumed to occur at a constant probability, irrespective of individual and/or location characteristics
Rare event
Transition probability depends on individual and/or location characteristics
Work in progress