Innovation, human capital destruction and firm's in training

We analyse the effeect of human capital obsolescence due to the introduction of technological innovations on the long-run growth rate, and show that in equilibrium the pace of technical change may be faster than is socially optimal. In such cases, the existence of market imperfections, and their costs for firms, may improve the welfare for the society as a whole. In particular, we assume that ¢rms do not have full information on workers' skills but can arrange some form of internal training that permits them to acquire the lacking information. Training costs reduce research and development investments by firms and in this way draw the market equilibrium closer to the social optimum.