Temporal stability of preferences: The case of COVID-19 vaccines in Australia and New Zealand.

This paper introduces a novel two-level Latent Class (LC) structure to investigate the temporal stability of preferences, allowing individuals to switch classes over time. The model is used to investigate the temporal stability of COVID-19 vaccine preferences in Australia (AUS) and New Zealand (NZ) during 2020-2021. Through online experiments on vaccine choices, stated choice data is collected across three waves from the general population in both countries. The LC estimation identifies three distinct preference classes: an "Impatient" group, with greater sensitivity to waiting time (AUS: 46%, NZ: 31%), a "Price Sensitive" group (AUS: 41%, NZ: 56%), and a "Vaccine Hesitant" group (AUS: 13%, NZ: 13%). Across waves, preferences for COVID-19 vaccines remain stable, with the probability of respondents remaining in the same class over three waves being 0.62 for Australia and 0.61 for NZ. Changes in preferences are significantly linked to variations in individuals' socioeconomic status and COVID-19 policy responses during the survey period.