This paper introduces an economically meaningful concept of generality of an input and defines a coefficient of technological generality, an intuitive measure of congruence in the R&D required for improving the quality of various adaptations of a general purpose input. It is shown in a monopolistic competition model with heterogeneous firms that if the proposed coefficient is less than zero, then firms would prefer to outsource the R&D and production of the input to a specialized supplier in the long run, and specialization will lead to faster output growth. If coefficient is greater than zero, output growth is slower under specialization and specialization cannot be a long run equilibrium. Further, if the coefficient is zero then whether or not specialization occurs is governed by considerations that have been put forward in existing models, and specialization has no impact on the rate of output growth.