An extension of the generalized matching law incorporating context effects on terminal‐link sensitivity is proposed as a quantitative model of behavior under concurrent chains. The contextual choice model makes many of the same qualitative predictions as the delay‐reduction hypothesis, and assumes that the crucial contextual variable in concurrent chains is the ratio of average times spent, per reinforcement, in the terminal and initial links; this ratio controls differential effectiveness of terminal‐link stimuli as conditioned reinforcers. Ninety‐two concurrent‐chains data sets from 19 published studies were fitted to the model. Averaged across all studies, the model accounted for 90% of the variance in pigeons' relative initial‐link responding. The model therefore demonstrates that a matching law analysis of concurrent chains—the assumption that relative initial‐link responding equals relative terminal‐link value—remains quantitatively viable. Because the model reduces to the generalized matching law when terminal‐link duration is zero, it provides a quantitative integration of concurrent schedules