The Effect of Changes in Real Income and Relative Price on the Share of a Sector, with Special Reference to the Public Sector
论证了在分析部门份额增长时，除收入效应外还需纳入价格效应，并探讨了公共部门与私人部门间生产率差异导致的相对价格变化对部门份额的影响。
Income effects are of major importance in most models that describe the sector. The aim of this article is to demonstrate the importance of also including price effects when treating the equilibrium and stability properties of such models, i.e. when discussing what factors may arrest the growth in the share of the sector before it approaches absurd levels. The importance of prices is shown to be weakened if the covariations between the share and income elasticities are as expected, i.e. positive for private and negative for public goods. The properties of the analysis also make it applicable to general sectoral growth problems. During the past few decades there has been a fairly strong increase in the relative size of the sector in many countries. The change has been less when measured in constant rather than current prices. The reason for this difference is of course that the measured increase in productivity is smaller for goods and services (in a broad sense) of the sector than for ordinary private goods. To some extent the difference reflects the difficulties involved in measuring real output of the sector. This practical problem explains only part of the development, however, and will not be treated here. Instead, we deal with the consequences, for a sector, of changes in real income and relative prices due to changes in relative productivities, assuming that these changes are real and not a result of measurement problems. Accordingly, the scope of the analysis is relatively general, and the relation between the private and the sector is only the most obvious example. Thus the analysis may also be regarded as a contribution to the general literature on pectoral growth, e.g. primary, secondary and tertiary sectors. In order to facilitate the discussion of the special problems as regards the sector in Sections V and VI, we denote the variables by the subscripts g