On Pajamas Media Dalrymple describes a recent, surprising realization:

Although I have spent much of my career exploring the less meritorious aspects of human conduct, there is a type of research fraud that I had not suspected to exist until I recently read an article in the New England Journal of Medicine. Once you know that volunteers for pharmacological experiments are paid, it becomes obvious, and I feel slightly foolish for not having realized it before: the volunteers also commit fraud.