APPLICATIONS OF SPECTRAL ANALYSIS

The basic concepts and application of spectral analysis are explained. Stationary time series and autocorrelation are first defined. Autocorrelation is related to the familiar concepts of variance and covariance. The use of autocorrelation analysis is explained in estimating the interdependent relationship of a time series over discrete time lags. In order to measure the behavior of the time series using autocorrelation, it would be necessary to examine a very large number of autocorrelation lags. Alternatively, the technique of Fourier analysis can be used to transform the autocorrelation function of the time series into a continuous function, termed a spectrum. The spectrum has a one to one correspondence to the autocorrelation for the time series and has the advantage of representing all possible autocorrelations over the discrete time lags. The spectrum can then be examined as a measure of the behavior of the time series. Spectral analysis indicates the reliability of the analysis of autocorrelated variables when familiar statistical techniques such as sample means and variances are used. The application of spectral analysis to management science problems in three general areas is illustrated: (1) inventory demand, (2) transportation simulation, and (3) stock market price behavior. Spectral analysis was used to detect cycles and trends in the data. Analyses were focused on the spectrum which provides a measure of the relative contribution of cycles in a band of frequencies to the total variance of the data.     

Social Work, Social Science and Practice Wisdom

Correspondence to Michael Sheppard, Department of Applied Social Science, University of Plymouth, Drake Circus, Plymouth PL4 8AA. Summary Social work has for some time had an ambiguous and ambivalentrelationship with its social science knowledge base. However,this has arisen, at least in part, because of the emphasis onthe outcome or product of social science rather than the processby which research is conducted. This paper, focusing on assessment,argues that an emphasis on process goes some way to closingthe gap between social science and social work, that the methodsused by social researchers are, in many respects, simply refinementsof the methodology of everyday life, and that social workers,when conducting assessments operate rather like practical qualitativeresearchers. Using Analytical Induction as an heuristic device,it proceeds to explore critical characteristics of good practicein social work assessments. It concludes that practice shouldbe characterized by critical awareness, involving imaginativedevelopment of alternative hypotheses, a sceptical attitudetowards case assessments and a principle of adopting hypothesesleast likely to be in error.     

A COUNTRY RISK INDEX: ECONOMETRIC FORMULATION AND AN APPLICATION TO MEXICO

Dynamic factor analysis is used to estimate a monthly country risk index for Mexico. This method extracts the unobservable risk information contained in deviations from interest rate parity and allows for hypothesis tests regarding the important determinants of such risk. The results suggest that the ratios of imports to reserves and debt to exports are important determinants of Mexican country risk. The estimated risk index correctly anticipates the Mexican capital controls and financial crisis of August 1982. In addition, the index significantly leads the country risk rating published by Institutional Investor based on commercial bank surveys.     

Supervision, Role Strain and Social Services Departments

Correspondence to Department of Social Work and Social Administration, University of Western Australia, Nedlands, Western Australia, 6009 Summary The paper analyses the potential for ambiguity and ambivalencetowards the supervision of practice in social services departments.While supervision may be integral to much social work practicein clinical settings, the culture and tradition of supervisionin social services departments looks to be permeated with confusionabout ‘supervision’ or ‘consultation’,the nature of accountability and the functions of supervisionof qualified and experienced practitioners. To move beyond anideology prescribing supervision, the paper considers evidenceof the effectiveness of supervision practice, analysing thetransition from practitioner to line-manager/supervisor andthe subsequent strain on the supervisor's authorities of positionand of expertise in some current arrangements for supervisionin field-work ‘teams’. Finally, there is an unequivocalassertion that effective supervision is an essential componentin the monitoring of client service and the maintenance of practitionersengaged in stressful forms of practice. Such supervision needsto recognize the managerial and administrative tasks necessaryto protect the agency and the client from poor quality practice,while also respecting the emotional and educational needs ofnewly qualified and experienced practitioners exposed to thedemands of high-risk judgement and practice.     

UNDERPAID and OVERWORKED: MEASURING THE EFFECT OF IMPERFECT INFORMATION ON WAGES

This paper investigates the degree of shortfall between the wages workers earn and what they could earn assuming perfect or costless information in the labor market. We use the stochastic frontier regression technique to estimate the degree of shortfall found in wages on an individual basis. The paper tests, in addition, a number of hypotheses supplied by search theory in this context. The results generally confirm the propositions from search theory and indicate that, on the average, worker wages fall short of worker potential wages by approximately 10 percent.     

‘Customs in common’: The epistemic world of the commons scholars

Theory and Society -     

GOVERNING A GROUNDWATER COMMONS: A STRATEGIC AND LABORATORY ANALYSIS OF WESTERN WATER LAW

We examine strategic behavior in groundwater depletion within the setting of state governance of groundwater resources in the American West. Solving a dynamic common-pool resource model for its optimal solution and its subgame perfect equilibrium provides benchmarks for behavior observed in laboratory experiments. Three forms of legal rules—common-pool depletion with a "rule-of-capture" to establish ownership (absolute ownership doctrine), entry restrictions (prior appropriation doctrine), and stock quotas (correlative rights doctrine—are examined in terms of their impact on individual strategic behavior in laboratory experiments.     

THE RATE OF RETURN TO MEXICAN AMERICANS AND ANGLOS ON AN INVESTMENT IN A COLLEGE EDUCATION

Rates of return to an investment in a college education are estimated for Mexican American and Anglo male college graduates with majors in business, accounting, education and liberal arts. The returns, estimated for 1967, 1970 and 1973 graduates of Pan American University, are quite substantial for all but the Anglo education majors. The returns to the business and accounting majors substantially exceed those to the other graduates. There was no strong tendency for the rates of return to fall over time nor were there any systematic differences between the returns to the two ethnic groups. This latter result does not imply an absence of labor market discrimination against Mexican American college graduates.     

TEACHING TOOLS: TEACHING METHODS IN UNDERGRADUATE ECONOMICS

Lectures have long been the dominant pedagogical approach in undergraduate economics courses, but they are certainly no longer the exclusive approach. Much of the recent soul-searching in the discipline, dealing with the desirable characteristics of economics programs and their graduates, has largely ignored the issue of promoting the use of innovative and more active forms of teaching and learning. We review a considerable literature on new teaching approaches, developed by economists over the past twenty-five years, and argue that this should also be a part of the current debate about curriculum and training reforms for the profession.