Many contemporaneously aggregated variables have stochastic aggregation weights. We compare different forecasts for … and the aggregation weights, and a forecast which aggregates univariate forecasts for individual disaggregate components … and the aggregation weights. In empirical illustrations based on aggregate GDP and money growth rates, we find forecast …

explicit aggregation over firms. The aggregate model is estimated for the FRG. …

Aggregation may be harmful but cannot always be avoided in the analysis of complex econometric models. It should be … carried out intelligently by choosing ein aggregative model optimally for modes of aggregation speeified in advance, i ….e. minimizing the bias introduced by aggregation and mea-sured by a formula based on the mean-square forecast error. This leads to …

of the problem of choosing an aggregative model optimally for modes of aggregation specified in advance leads to a … formula for the aggregation bias based on the mean-square forecast error. Taking this formula as objective function one would … wish to choose a grouping that minimizes aggregation bias. Unfortunately this results in an optimization problem of a high …