"There is no universal definition of the term 'sector of industry'; sectors should be demarkated according to the objectives of respective studies, if they are going to make any sense. Based on a few criteria for consistency as well as substantially adequate statistical data and economic categories, a systematisation of the problem at hand should define a sector of industry as a subsection of companies of the economy which offer similar goods characterised by use or typical materials. To understand structural change, which is linked with marked developments, requires a system of disaggreation according to categories of goods. Generally valid statements on the detail of this disaggregation cannot be made. If a very detailed disaggregation system is applied, in the extreme case the maldevelopment of an individual firm could skew the results at the macroeconomic level. In other words, this situation involves dimensions related to the economic regulatory concept of the free market. In general, at most for the individual case, a size category should be determined at which point the management of economic, social and technical changes should no longer be the affair of individual firms, but rather of the state. The economic situation of a sector of industry is always influenced by the macroeconomic development as well. However, the idea that structural changes can be empirically precisely separated from the phenomena of business cycle performance contradicts the result of economic research. This judgement is confirmed by a descriptive ex post analysis: Although there are reasons why the individual sector is greatly dependent on the business cycle, the reasons for outright economic weakness in other areas are probably far more complex. Moreover, ostensibly necessary forecasts of future structural changes are not precise enough. Projections of possible sectoral and macroeconomic development trends, as seen in econometric models, are always limited by the respective assumed constraints. False assumptions of exogenic constraints expected in the future - here primarily exchange rates, the prices of raw materials as well as monetary and fiscal premises - are thus reflected by the corresponding consequences for the accuracy of the forecast values.In summary it has been established that § 63, Sec, 4 could be in conflict with the principles of the free marktet, according to which the state should help easc the sectoral structural change, but should not permanently influence it. The authors arrive at the conclusion that there are no intersubjective concrete criteria for checking 'grave structural change of the economic situation in a sector of industry'. Paragraph 63, Sec. 4, which is vaguely worded, should therefore be phased out or replaced by a more practical formulation - e.g. by general regulations for checking individual cases." (Author's abstract, IAB-Doku) ((en))
