Great question. As a former editor of an international journal I can see where this question is coming from. You'd like to know the chances that a paper sent to the journal will end up being accepted. I think there are two issues. The journal has an empirical rejection rate -- basically the probability that a paper that is submitted to the journal is rejected. Suppose this is X. (It may be quite high, and usually very high rejection rates are associated with the most prestigious journals). It is a conditional probability -- GIVEN that the paper is submitted (and has presumably gone through some internal self selection by the author to target the right journal....) A random inappropriate paper has, I would assume, have a much higher probability of rejection if it is ill-suited. Assume that over time the journal's reputation becomes well known and the effort to publish unsuited material gets smaller. So over time the core papers submitted to the journal are already presorted into a roughly appropriate stratum. Thus the interpretation of the rejection rates has to be done carefully. The acceptance rate may appear to be quite high because of the selection bias.