In this paper we explore the implications of normative principles for the evaluation of population health. We formalize those principles as axioms for social preferences over distributions of health for a given population. We single out several focal population health evaluation functions, which represent social preferences, as a result of combinations of those axioms. Our results provide new rationale for popular theories in health economics, such as the unweighted aggregation of quality-adjusted life years (QALYs) or healthy years equivalents (HYEs) and generalizations of the two, aimed to capture concerns for distributive justice, without resorting to controversial assumptions on individual preferences.