Modelling the Effect of Health Risk Perception on Preferences and Choice Set Formation over Time: Recreational Hunting Site Choice and Chronic Wasting Disease

Abstract

Chronic wasting disease (CWD) is a prion disease that affects deer, elk and other cervid wildlife species. CWD is essentially the cervid form of “mad cow disease” or Bovine Spongiform Encephalopathy (BSE). However, unlike BSE there is no known link between the consumption of CWD affected meat and human health. Nevertheless, hunters are advised to have animals from CWD affected areas tested and are advised against consumption of meat from CWD infected animals. In this paper we model hunter response to the knowledge that deer in a wildlife management unit (WMU) have been found to have CWD in Alberta, Canada. We examine hunter site choice over two hunting seasons using revealed and stated preference data. We model preferences, choice set formation, and scale (variance) as a function of attributes, time period and demographics. The availability function approach (Cascetta and Papola, 2001) is applied to approximate choice set formation or endogenous choice set analysis. We also compare this approximation to a fully endogenous choice set model using the Independent Availability Logit model (Swait, 1984). We find that CWD incidence affects choice set formation and preferences. Availability of an alternative in a choice set is negatively affected by CWD and this effect appears to be increasing over time. Thus modeling CWD in terms of its effect on preferences only would result in biased estimates of impact. Furthermore, the error variance is increasing over time, possibly arising from additional uncertainty about the impact of CWD and the spread / prevalence of the disease. However, our comparison between the availability function approach and the fully endogenous choice set formation model suggests differences between these two approaches.