Sheffield Economic Research Paper Series
October 15, 2012
We introduce the (panel) zero-inflated interval regression (ZIIR) model, to investigate GP
visits using individual-level data from the British Household Panel Survey. The ZIIR is particularly
suitable for this application as it jointly estimates the probability of visiting the GP and then,
conditional on visiting, the frequency of visits (defined by given numerical intervals in the data). The
results show that different socio-economic factors influence the probability of visiting the GP and the
frequency of visits.