Information integration in risky decision making was studied by using a functional measurement approach. Participants (N=84) played a computerized risky card game incorporating a within-subject design with the 3 factors (a) probability of negative or positive outcome, (b) amount of gain, and (c) amount of loss. Results on the group level showed mainly additive patterns of integration. Observed deviations from the general pattern could be explained more detailed by the results of the individual analyses: There was a wide range of different strategies from centration to additive and mixed additive-multiplicative strategies. The most frequent rules of integration were additive; pure multiplicative rules were rarely found. These findings give support to additive models in risky decision making. However, individual differences in risky decision making strategies appear to be a topic that deserves further study.