Composite ${pi}$-structure analysis has been proposed for predicting relative isomer stabilities based on nonbonded effects: all the possible crowded ${pi}$-structures are identified for each isomer, and the systems are represented by abbreviated notation of $(n{pi}/m)$ : then using simple rules and additivity of the nonbonded effects, the order of stability can be determined. A number of examples are given in support of this analytical procedure.