AbstractAlthough the concept of relevance (or weight) of inputs plays a central role in equity theory, it has not been clearly defined. The present investigation attempts to answer the question of when, and which, inputs are taken into account in allocation decisions. Subjects were given a stimulus story in which two fictitious persons had, through joint work, produced a monetary gain or loss; further, information was provided on the relative effort (amount of time worked intensively) and /or ability (as determined by a test) that each stimulus person had contributed. Subjects were asked how they would allocate the gain or loss.Empirical evidence for the following three codeterminants of allocation decisions was obtained: (1) the type of input—personal and behavioural characteristics are [relevant] for allocation if they are perceived as (a) causallv important for outcome production, (b) variable, and (c) under the person's volitional control; (2) the type of outcome to be allocated—more equal allocations are observed when loss as opposed to gain must be allocated; and (3) the constellation of individual inputs on given dimensions—information is given on several input dimensions, a dimension which should be [irrelevant]according to criteria (a), (b), and (c) does codetermine allocations when recipients have contributed equally with respect to this dimension. The latter finding is discussed from the perspective of [cognitive alg