Background As the UK’s main healthcare priority-setter, the National Institute for Health and Care Excellence (NICE) has good reason to want to demonstrate that its decisions are morally justified. In doing so, it has tended to rely on the moral plausibility of its principle of cost-effectiveness and the assertion that it has adopted a fair procedure. But neither approach provides wholly satisfactory grounds for morally defending NICE’s decisions. In this study we adopt a complementary approach, based on the proposition that (...) a priority-setter's claim to moral justification can be assessed, in part, based on the coherence of its approach and that the reliability of any such claim is undermined by the presence of dissonance within its moral system. This study is the first to empirically assess the coherence of NICE’s formal approach and in doing so to generate evidence-based conclusions about the extent to which this approach is morally justified. Methods The study is grounded in the theory, methods and standards of empirical bioethics. Twenty NICE policy documents were coded to identify and classify the normative commitments contained within NICE technology appraisal policy as of 31 December 2021. Coherence was systematically assessed by attempting to bring these commitments into narrow reflective equilibrium (NRE) and by identifying sources of dissonance. Findings Much of NICE policy rests on coherent values that provide a strong foundation for morally justified decision-making. However, NICE’s formal approach also contains several instances of dissonance which undermine coherence and prevent NRE from being fully established. Dissonance arises primarily from four sources: i) NICE’s specification of the principle of cost-effectiveness; ii) its approach to prioritising the needs of particular groups; iii) its conception of reasonableness in the context of uncertainty, and iv) its concern for innovation as an independent value. Conclusion At the time of analysis, the level of coherence across NICE policy provides reason to question the extent to which its formal approach to technology appraisal is morally justified. Some thoughts are offered on why, given these findings, NICE has been able to maintain its legitimacy as a healthcare priority-setter and on what could be done to enhance coherence. (shrink)