'Data fusion techniques merge data sets of different survey samples. This merging of data sets is done by means of statistical matching on the basis of common variables. As a result a virtual sample of complete, but artificial nature is generated. Because being completely unobserved the missing information of an individual in one sample is imputed using the observed data values of any other individual which is found to be the (most) similar one in the other sample. This paper analyses the power of data fusion techniques. The parameters of the (marginal and joint) distributions of all variables in the artificial sample are formulated. The correlation between variables not jointly observed which can only be estimated by means of the matched f...