Aggregation Problem in Input Output Analysis - A Survey

The problem of aggregation in the input-output analysis arises in two cases : (a) the construction of the input-output table; (b) application of the model for forecasting sectoral output. We shall confine our attention to the second case. A considerable amount of theoretical and empirical work has been done with regard to this case: given the input-output table, how can we aggregate for a specific purpose?.