Implementations of the present disclosure relate to a method, system and program product for determining a causality between a plurality of variables. Specifically, a method is provided for determining a causality between a plurality of vectors, which comprises: in response to a data set of a plurality of samples associated with the plurality of variables being collected, obtaining a matrix describing the causality between the plurality of variables, each sample among the plurality of samples comprising data that corresponds to the plurality of variables; determining fitness associated with the causality and sparsity associated with the causality based on the data set and the matrix, wherein the sparsity comprises a constraint on each vector among a plurality of vectors in the matrix, the constraint corresponding to a variable among the plurality of variables; building a first problem formula describing the causality according to the determined fitness and sparsity; and solving the built first problem formula so as to obtain a candidate result of the matrix. Further, there is provided a corresponding system and computer program product.