Production (manufacturing) flexibility is one of the dominant requirements of the present engineering industry. Automated assembly systems have a special position because of their technical and technological complexity. At the present the problem of determination of existing or planned assembly systems flexibility is elaborating at the many research workplaces. The attention is focused on to elaborating of the base methodical steps for determination of a relative similarity of objects group (assembly parts and assembly grippers) with suitable statistical methods utilisation. The dichotomous parameters were defined for the objects similarity valuation.