There are of course problems with measuring productivity only in value or money terms. For example, a bad harvest may reduce the *physical* amount of cotton in half, although this cotton would represent as much *value* as twice that amount in the previous good harvest year. If we were thinking in terms of a vertically integrated sector, half of the spindles and looms would have to be shut down because of the the shortage of cotton, i.e., the technical scale would be halved; but the *value* of the final output may remain the same. While the capitalist could remain content with the maintainence of productivity in value terms, Marx wrote about such a one sided approach, characteristic of the classical economists: "By denying the importance of gross revenue, i.e., the volume of production and consumption--apart from the value surplus--and hence denying the importance of life itself, political economy's abstraction reaches the peak of infamy."
yours, rakesh