"Happiness research in economics takes reported subjective well-being as a proxynmeasure for utility and has already provided many interesting insights about human well-beingnand its determinants. We argue that future research on happiness in economics has a lot ofnpotential, but that it needs to be guided more by theory. We propose two ways to test theories ofnhappiness, and illustrate them with two applications. First, reported subjective well-being canncontribute towards a new understanding of utility in economics. Here, we study the introductionnof income aspirations in individuals’ utility functions in order to improve our understanding ofnhow income affects individual well-being. Second, happiness data offers a new possibility ofndiscriminating between different models of behavior. This is studied for theories of marriage,nwhich crucially depend on auxiliary assumptions as to what contributes to well-being innmarriage. Both applications are empirically tested with panel data for Germany."