Evaluation of cross-section data for various collision processes is now being made by many groups. But the results (i.e., recommended data) are often different from each other depending on who evaluates them. An evaluation (or validation) of the evaluated data is necessary. Three examples of the activity are shown here: (a) consistency check of the total scattering cross section, (b) calculation of the swarm parameters, and (c) chemical modeling. For the first two cases, a demonstration is performed with the use of the cross-section sets recommended for the electron collisions with N2 and O2 by the present author.