This definition suggests four necessary aspects of undue inducement: 13 (1) an offered good—individuals are offered something that is valuable or desirable in order to do something;(2) excessive offer—the offered good must be so large or in excess that it is irresistible in the context;(3) poor judgment—the offer leads individuals to exercise poor judgment in an important decision;(4) risk of serious harm—the individuals’ poor judgment leads to sufficiently high chance that they will experience a harm that seriously contravenes his or her interests. As related specifically to clinical research, undue inducement typically means that individuals are offered financial payment, medical services, or some item of value such as a shirt, toothbrush, or transport of a casket for burial that is so attractive it leads them to exercise poor judgment to either overestimate short-term benefits or underestimate long-term costs. Because of this poor judgment, they enrol in a research trial that poses a substantially unfavourable risk-benefit ratio, thereby compromising their interests. 5–8, 11, 13

Each of these elements is necessary for inducement to be undue; without any one there is no undue inducement. Harm without poor judgment—being struck by lightning—is just misfortune. Harm from poor judgment without an offered good—swimming in crocodile infested waters—is imprudence. Importantly, some harms are relatively minor or mild. They might be embarrassing, annoying, unfortunate, or even painful, but are neither sufficiently severe nor permanent to constitute undermining of a person’s fundamental interests. 9–14 For instance, being embarrassed at participating in a reality TV programme, sustaining a painful but transient injury from trying a new sport, or selecting a boring job for a higher salary are harms, but these are minor or transient harms. Undue inducement requires substantial risk of serious physical, psychological, economic, or others harms, which threaten a person’s fundamental interests. Although reasonable people might disagree about the seriousness of some risks, undue inducement relates to risks that are clearly unreasonable. The kinds of harms that people assume and sustain in everyday life are reasonable because they are not of sufficient magnitude or seriousness to constitute the substantially unfavourable risk-benefit ratio necessary for undue inducement. Furthermore, the evaluation is not of harms posed by individual elements. 15 Many isolated factors—actual work or an injury—can be harmful or undesirable in themselves. When the work is balanced by the salary or the risk of injury by the exhilaration of a sport, the riskbenefit ratio must not be excessively unfavourable. The key ethical issue is not the harm of each individual element, but the net risk-benefit ratio. 15