The Effects of Honesty Oath and Consequentiality in Choice Experiments

Choice experiments are now one of the most popular stated preference methods used by economists. A highly documented limitation of stated preference methods is the formation of hypothetical bias in the estimation of consumers’ willingness-to-pay (WTP) for a good or a service. Honesty oaths and consequentiality scripts are two ex ante approaches that show promise in their ability to reduce or eliminate hypothetical bias. We examine these approaches independently and together and measure their effectiveness by comparing the resulting WTP values. We also explore a potential connection between consequentiality, honesty oaths, and attribute non-attendance (ANA). We infer patterns of ANA resulting from our various treatments (i.e., consequentiality script only, honesty oath only, combined script and oath, inconsequential, and control) and examine the differences. Our results suggest that the combined ex ante approach of consequentiality script and honesty oath provided significantly lower WTP values than all other experimental treatments. Conditioning our data for both consequentiality and ANA resulted in significant improvements in model fit across all treatments. Results indicate that not accounting for ANA has important implications for welfare estimates. While we cannot fully explain the connection, the combination of the consequentiality script, honesty oath, and inferred ANA allowed us to better see the differences between respondents’ attending attributes and those ignoring.