 Two morals emerge from these reflections. First, self-report measures of happiness could be reliable guides to relative happiness, though telling us little about how happy, in absolute terms, people are. We may know who is happier, that is, but not whether people are in fact happy. Second, even comparisons of relative happiness will be inaccurate if the groups being compared systematically bias their reports in different ways. This worry is particularly acute for cross-cultural comparisons of happiness, where differing norms about happiness may undermine the comparability of self-reports. The French might report lower happiness than Americans, for instance, not because their lives are less satisfying or pleasant, but because they tend to put a less positive spin on things. For this reason it may be useful to employ instruments, including narrower questions or physiological measures, that are less prone to cultural  biasing.[12]