Forecasts guide decisions in all areas of economics and finance. Economic policy makers base their decisions on business cycle forecasts, investment decisions of firms are based on demand forecasts, and portfolio managers try to outperform the market based on financial market forecasts. Forecasts extract relevant information from the past and help to reduce the inherent uncertainty of the future. The topic of this special issue of the Journal of Economics and Statistics is the theory and practise of forecasting and forecast evaluation and an overview of the state of the art of forecasting.

A macroeconomic disequilibrium model is developed for the Federal Republic of Germany. Starting with a microeconomic model of firm's behaviour, the optimal dynamic adjustment of employment and investment is derived. The model of the firm is complemented by an explicite aggregation procedure which allows to derive macroeconomic relations. The model is estimated with macroeconomic data for the Federal Republic of Germany. An important feature is the consistent introduction of dynamic adjustment into a model of the firm. A new method is the particular approach of a delayed adjustment of employment and investment. The estimation results show significant underutilizations of labour and capital and indicate the importance of supply constraints for imports and exports. As the most prominent result, they reveal the importance of the slow adjustment of employment and investment for the macroeconomic situation in Germany and especially for the persistence of high unemployment in the eighties.

The recent development of endogenous growth theories has renewed the in terest into the sources of productivity growth of the advanced industrialized economies. The basic advance of these models is that the evolution of tech nological progress is explained endogeneously within the economic model. The most important concept is the idea of endogenous, market-driven inno vations which are seen as the basic source of technological advances. Firms develop sophisticated production techniques and new products in order to reduce costs or to stimulate demand. Equally important is the concept of knowledge spillovers from innovation activities and scale economies associ ated with them. External effects drive a wedge between private and social re turns of innovation activities, and scale economies affect the market structure. In addition, each year's productivity increases exhibit an enormous social value. Therefore, the analysis of endogenous innovations, scale economies, and knowledge spillovers has important implications for economic policy which enhances the interest into empirical investigations of these issues. This book is a collection of theoretical and empirical work on this subject. It combines micro economic and macroeconomic issues; a special emphasis is placed on empirical applications. Much work has been devoted to the search and the preparation of appropriate data, and all models are estimated with panel data. The first two chapters take an aggregate view at the growth process."