Repeat self-harm: application of hurdle models.

Among those who present to the emergency department for self-harm, many will repeat. Self-harm repetition is an outcome of interest in both observational and intervention studies. However, few such studies analyse the number of repeat self-harm presentations. Here, hurdle models are introduced as a potentially useful statistical method for these analyses. Emergency department data from the Province of Ontario, Canada, are used to illustrate an example of implementing hurdle models and interpreting their results.