STATISTICAL analyses of the structureperformance relationship in manufacturing industries have invariably assumed that an industry's member firms differ only in their market shares. This paper demonstrates that this assumption is often incorrect, and that the complexity of the structure of strategic groups populating an industry exerts a significant influence on its performance. In the following sections we explain the sources and significance of strategic groups, derive hypotheses about their influence on an industry's profitability, and test these hypotheses on a sample of producer-good industries.

Automatic fuel adjustment mechanisms (FAM), which allow utilities to charge higher rates as fuel costs increase, are shown to disrupt the balance of economic efficiency provided for by regulatory lag. A model is developed to analyze efficiency changes caused by asymmetrical inputs and to examine the economic implications of broadening FAM to include the cost of labor, supplies, and purchased power. The conclusions are reached that efficiency is promoted by regulatory lag and formal hearings and that policies that circumvent these procedures reward inefficient behavior in terms of utility investment decisions. 13 references.

R ECENT theoretical and empirical analysis of unemployment has emphasized its dynamic character: flows into and out of unemployment are very substantial in relation to the stock of unemployed individuals,' and groups with high unemployment rates tend to be those whose members experience short but frequent spells of joblessness (Hall, 1970). This view of unemployment has afforded important new insights into the question of why average unemployment rates differ so markedly across certain labor force groups, and has led to major shifts in the focus of labor market policy. For example, the discovery that the higher unemployment rates of blacks are due almost entirely to the higher frequency of jobless spells they experience (Perry, 1972) has shifted emphasis away from policies that stimulate demand toward policies that will help to reduce job turnover. Existing studies have focused almost exclusively on differences in the average values of the duration and frequency of spells of unemployment between certain labor market groups; none has examined systematically the variation in unemployment spell lengths and frequencies across individuals. This paper seeks to fill this gap by examining the relative contributions of unemployment frequency and unemployment duration to the distribution of total hours of unemployment across individuals within each of several important labor force groups. Dispersion in the distribution of unemployment across individuals results when either the length or frequency of unemployment spells is unevenly distributed across individuals. This dispersion is reinforced when the length and frequency of spells are positively correlated, i.e., when those individuals who have the greatest difficulty finding jobs (the last hired) tend to be the same individuals who experience the greatest difficulty keeping them (the first fired). The principal contribution of our study is that it enables the variations in individual unemployment experience to be linked explicitly to individual variations in the length and frequency of unemployment spells. Section II below outlines a probabilistic model of individual labor market transitions that serves as the basis for our empirical estimation procedures. In section III we then describe the data employed in our study (the National Longitudinal Survey) and present our estimates of the distributions of individual transition probabilities for each of four demographic groups. Section IV examines the effect of a business cycle downturn on the unemployment experienced by individuals in these groups.

PERSONAL saving rates, i.e., the ratios of personal saving to personal disposable income, in many industrialized countries have risen dramatically in recent years. A number of attempts to explain the phenomenon of rising saving rates coinciding with price inflation have drawn upon the work of George Katona (1975), who has stressed the feeling of uncertainty and pessimism about the future caused by inflation that, in turn, encourages saving. In this paper a general model of aggregate household saving behavior is formulated. Data on Canada, Germany, Japan, the United Kingdom, and the United States are used to estimate the personal saving function in each of the countries and the results are used to test various hypotheses about personal saving behavior. This paper has two major objectives: to test for a direct influence of inflation on personal saving after taking into account the influence of other relevant factors, including any indirect channels by which inflation may exert an influence (e.g., the level of real liquid assets); and to determine what factors in each country are important for explaining saving behavior.

Albert A. Hirsch, Saul H. Hymans, Harold T. Shapiro, Econometric Review of Alternative Fiscal and Monetary Policies, 1971-75, The Review of Economics and Statistics, Vol. 60, No. 3 (Aug., 1978), pp. 334-345

Ernest H. Oksanen, James R. Williams, International Cost Differences: A Comparison of Canadian and United States Manufacturing Industries, The Review of Economics and Statistics, Vol. 60, No. 1 (Feb., 1978), pp. 96-101