The degree of export fluctuations and its impact on income have been subject to a number of investigations. A major bone of contention has been whether developing countries experience a greater degree of fluctuation in exports than developed countries, and whether such fluctuations affect the growth-rate of developing countries. This study examines this contention y constructing comparable econometric models for 11 countries, including both developing and developed countries. From these models it seeks to derive the export-income multiplier which can throw light on the question as to which countries are affected more than others by export fluctuations. The study shows that the long-run multiplier relating to both income and investment are generally larger for developing countries than for developed countries. In addition, for each country the dynamic multipliers have been used to derive the income path which is attributable to changes in exports as they actually occurred. The income path has been derived on the assumption that “real” exports grow at a constant rate every year. A comparison of these two simulated income series definitely shows that an increase in the instability of exports leads to an increase in the instability of income in every country. However, the impact of instability in exports on income growth rate is not in the same degree in all counties. In the case of only five countries, there is a decline in growth rate when there is an increase in instability of exports, even though a cross country regression shows that in general countries with higher instability in exports have on the average a lower growth rate.

The article focuses on joint variance in cost accounting. A number of recent cost accounting texts discuss a three-variance standard cost analysis consisting of a pure price variance, a pure quantity variance and a joint variance, which is due to the interaction of price and quantity differentials. The explicit treatment of the joint variance facilitates understanding of variance analysis generally; and is particularly useful in explaining why, in a two-variance analysis, the quantity or usage variance usually is based on standard price and the price or spending variance usually is based on actual quantity. Conditions, which produce a favorable or unfavorable joint variance, are not as apparent as with the other variances; and students often have difficulty with this point. Purposes of the paper note are to list these conditions for the joint variance and to present a graphical analysis, which can be useful in demonstrating relationships involved. Since the relationship between the joint variance and the price and quantity variances is multiplicative, the sign of the joint variance is independent of magnitudes of the price and quantity variances.

Contemporary problem of concern to all technology-rich industrialized societies is that of continuing to provide a high level of motivation for private enterprise while ensuring that its aggregate impact upon society is consistent with social goals and aspirations. This is an exceedingly complex problem for several reasons. Traditional performance criteria for private enterprise have emphasized results which may be in conflict with societal priorities. There are many divergent views as to the most desired social goals and aspirations. The qualitative dimensions of social goal formulation and evaluation add further to the complexity. Yet, the problem is of such significance that there is a pressing need to explore its many dimensions and find ways of formulating solutions. The nature of the problem can be related further to performance as it is typically viewed from a management perspective. A corporate management's attention, decisions and actions are focused more on those components of the firm's performance which are included in the firm's formal measurement system. To the extent that a firm's social impacts are not subjected to formal measurement process, these aspects are not likely to enter into the firm's planning decisions or performance evaluation.

There appears to be growing interest in the development and estimation of simultaneous equation models for finance. Simkowitz and Jones [11] stimulated much of this concern in their observations on the need for these structures. Moreover, Simkowitz's application to the modeling of security returns with Logue [12] provides some support for these suggestions. Recently Lloyd [6] has argued that there may be significant problems in using two-stage least squares (hereafter 2SLS) with such models as a result of the potential for contemporaneous correlation in the structural errors across equations. The purpose of this note is to question several of Lloyd's conclusions and to provide some evidence that his findings may not be representative for the broad array of simultaneous models applicable to financial problems.

T HE inferiority of southern black schools (especially rural schools) alleged by the Coleman Report (1966), coupled with the mass migration historically of southern blacks to northern cities, provides one potential explanation of the generally low returns to black education and of urban poverty in the nonSouth. Evidence from the 1960 Census suggests, however, that black migrants to the metropolitan North had higher incomes and less unemployment than blacks born there, even after controlling for differences in age, years of school completed, and a number of other variables (Masters, 1972). More recent evidence, confirming this pattern, from the 1967 Survey of Economic Opportunity (Weiss and Williamson, 1972) and the 1970 Census (Long and Heltman, 1974) also discounts the inferiority of southern black schools as an explanation of urban poverty in the non-South. In fact, the overall effect of a northern or even a large southern ghetto environment may be more harmful to black economic progress than a rural southern origin (Weiss and Williamson, 1972). In this paper we present results, using data from the National Longitudinal Surveys, that support the economic disadvantage of a nonsouthern ghetto environment for young black males. Controlling for differences in age, years of school completed, region and character of current residence, we find the mean earnings of young black males educated in the metropolitan non-South are substantially less than those of their peers educated in the rural South. We are unable to confirm this disadvantage for older black males, however. Several attitudinal and labor force characteristics of young blacks were examined to account for this pattern. The results suggest that a major problem in reducing black poverty lies in improving the environment of the nonsouthern ghetto. We also extend the analysis to whites in order to examine the rural-urban dimensions of environment and migration and their effect upon racial earnings differentials. The National Longitudinal Surveys, which provide the primary data for this paper, constitute a five-year longitudinal study of the labor market experiences of four subsets of the U.S. population: men 45 to 59 years of age, women 30 to 44 years of age, young men 14 to 24 years, and young women 14 to 24 years of age.1 For each of these cohorts a national probability sample of the noninstitutionalized civilian population was drawn by the Bureau of the Census. The present study is based upon data collected in the first round of interviews in 1966 with the two cohorts of men. Analysis is restricted to men whose current or last job reported in the survey week of 1966 was as a wage or salary earner. The self-employed are excluded to overcome the difficulty of separating income received as returns to physical capital from that received as returns to human capital. An additional universe restriction is included for the younger men's cohort to ensure they had been out of school for a minimum of 12 months. In section I we build upon earlier earningsfunctions studies by introducing variables which identify geographic origin of schooling. Section II explores the implications of our findReceived for publication January 28, 1974. Revision accepted for publication July 9, 1975. *This paper was prepared under a contract with the Manpower Administration, U.S. Department of Labor. We are indebted to Bennett Harrison, Ray Marshall, Herbert S. Parnes, and a helpful referee for comments on an earlier version of this manuscript. We especially thank Clarice Conger-Thompson, Gary Schoch, and Keith Stober for research and computational assistance. As is customary, the views expressed in this article are our own. I For a description of these surveys see Parnes (1972).