fatvegan

By convention, irrational traders and non-traders (participants who always chose the no cost option) were excluded prior to analysis.

Discrete Choice Experiment to Derive Willingness To Pay for Methyl Aminolevulinate Photodynamic Therapy Versus Simple Excision Surgery in Basal Cell Carcinoma

This is the sort of that often happens in discrete choice experiments. People whose decisions don't fit in with their assumptions are not considered worth including. In this case, people who always prefer to save money in making health care decisions (for skin cancer) are totally ignored. Those people are probably also the poorest, who may seem irrational or stubborn to comfortably off researchers, but most likely reflect the reality of not having much money. I can imagine someone conducting research on health care preferences of the uninsured and ignoring everyone whose decisions are dominated by cost.

The researchers will argue that they aren't interested in the poor and that they just want to get a general idea of what's going on. But when ignoring certain results is this arbitrary it becomes very easy to remove stuff for the wrong reasons. And when certain social groups are systematically excluded like this it's a bit troubling.