Experimental measurements of transient drop size distributions in a stirred liquid‐liquid dispersion (with low dispersed phase fraction) have been used concomitantly with population balance theory to recover the transition probability of droplet breakage, based on a similarity concept. The data remarkably uphold the proposed similarity hypothesis, and the estimated probability function displays the same qualitative trend as the model due to Narsimhan et al. (1979). Copyright © 1980 American Institute of Chemical Engineers