In restricting individual inputs to weak orderings of the alternatives, Arrow overlooked the possibility that people could input information about their preferences in the form of ordinal scores or grades. Graded inputs enable an “escape” from Arrow’s impossibility that is explained in Section 5.3. Amartya Sen extended Arrow’s framework to take into account not only ordinal information about people’s preferences among pairs of alternatives, but also cardinal information about the utility they derive from each one. In this way he was able to investigate the consequences of other assumptions than Arrow’s about the measurability and interpersonal comparability of individual preferences. See Section 5.4 and the entry social choice theory for details and references.