The Transition from School to Work: The Experiences of Blacks and Whites

Because much of the concern about youth unemployment is motivated by the large differences between the rates for blacks and whites, we have pursued our earlier work by analyzing separately for black and white youth the relationship between high school preparation and early labor force experience. We find no striking differences between the determinants of weeks worked by whites and non-whites upon graduation from high school. Although vocational training in high school bears little relationship to weeks worked upon graduation, hours worked while in high school bear a strong relationship to later employment for students and non-students, white and non-white. Academic performanceas measured by standardized test scores and high school class rank isalso positively related to later weeks worked by non-students, both white and non-white. Young persons find jobs in large part through friends and relatives or through direct application to employers orpossibly a combination of the two. Persons who are not looking forwork--and would then be classified as out of the labor force, according to standard definitions--are apparently quite distinct from personswho are looking for work. Those out of the labor force seem not tobe "discouraged workers" for the most part. Controlling for other individual attributes, non-whites are much more likely than whites to be in a post-secondary school full-time (although without controlling for these attributes the reverse is true). A large proportion of young men in school are also working part-time and a significant number are working full-time. A sizeable proportion of persons in post-secondary schools would be classified as unemployed based on official definitions. Indeed the unemployment rate among these full-time students is generally more than twice the rate among young men not inschool. Few high school graduates are chronically unemployed.

The Effects of the Minimum Wage on the Employment and Earnings of Youth

The employment and earnings effects of the minimum wage are estimated by parameterizing an hypothesized relationship between underlying market employment and wage relationships versus observed wage and employment distributions in the presence of a legislated minimum. If there had been no minimum during the 1973-78 period, we estimate that employment among out- of-school men 16 to 24 would have been approximately 4 percent higher than it in fact was. Among young men 16 to 19 employment would have been about 7 percent higher and among those 20 to 24, 2 percent higher. Employment among black youth 16 to 24 would have been almost 6 percent higher than it was, as compared with somewhat less than 4 percent for white youth. Although it is sometimes argued that the adverse employment effects of the minimum are offset by increased earnings, we find virtually no earnings effect. Had the minimum not been raised over the 1973-78 period, inflation would have greatly moderated the adverse employment effects of the minimum, with approximately two-thirds of the potential employment gains from elimination of the minimum attained. The weight of our evidence is inconsistent with a general increase in youth wage rates with increases in the real minimum. Our findings support the hypothesis that the effects of the minimum are concentrated on youth with sub-minimum market wage rates.

High School Preparation and Early Labor Force Experience

The relationship between high school training and work experience on the one hand and early labor force experience on the other are analyzed in the paper. In addition, the extent and nature of the persistence of early labor force experience is evaluated. The study is based on data for male youths from the National Longitudinal Study of the High School Class of 1972. While there appears to be no relationship between job-related training in high school and post-graduation weeks worked or wage rates, there is a strong relationship between hours worked while in high school and both weeks worked and wage rates in the first four years after graduation. High school class rank and test scores also are positively related to early weeks worked and wage rates in the labor force. It is also found that after controlling for individual specific characteristics of youth, there is little relationship between weeks worked in the first year after high school graduation and weeks worked four years later. And there is almost no relationship between initial wage rates and wage rates four years later, other than those attributable to measured and unmeasured individual specific characteristics. There is little persistence of early experience that cannot be attributed to heterogeneity among youth. There is, however, an effect of early work experience on later wage rates, although it is of modest magnitude in this sample of high school graduates.

Providing scientific visualisation for spatial data analysis: criteria and an assessment of SAGE

A consistent theme in recent work on developing exploratory spatial data analysis (ESDA) has been the importance attached to visualization techniques, particularly following the pioneering development of packages such as REGARD by Haslett et al (1990). The focus on visual techniques is often justified in two ways: (a) the power of modern graphical interfaces means that graphics is no longer a way of simply presenting results in the form of maps or graphs, but a tool for the extraction of information from data; (b)graphical, exploratory methods are felt to be more intuitive for non-specialists to use than methods of numerical spatial statistics enabling wider participation in the process of getting data insights. Despite the importance attached to visualisation techniques, very little work has been done to assess the effectiveness of techniques, either in the wider scientific visualisation community, or among those working with spatial data. This paper will describe a theoretical framework for developing visualisation tools for ESDA that incorporates a data model of what the analyst is looking for based on the concepts of "rough" and "smooth" elements of a data set and a theoretical scheme for assessing visual tools. The paper will include examples of appropriate tools and a commentary on the effectiveness of some existing packages

Discontinuous Distributions and Missing Persons: The Minimum Wage and Unemployed Youth

The effects of minimum wage legislation on the employment and wage rates of youth are estimated using a new statistical approach. We find that without the minimum, not only would the percent of out-of-school youth who are employed be 4 to 6 percent higher than it is, but also that these youth would earn more. In particular, the expected hourly earnings of youth with market wage rates below the 1978 minimum are 10 percent lower with the minimum than they would be without it. Thus, an effect of the minimum is to increase the concentration of non-employment among low-wage workers and to reduce their earnings relative to higher wage workers as well. The minimum wage accounts for possibly a third of the difference between the employment rates of black and white youth, according to our results. Our methodology is based on parameterization of the effect of the minimum on the distribution of "market" employment outcomes and market wage rates that would exist in the absence of the minimum. A concomitant of the estimation procedure is joint estimation of market wage and employment functions that would pertain if there were no minimum.

The empirical accuracy of uncertain inference models

Uncertainty is a pervasive feature of the domains in which expert systems are designed to function. Research design to test uncertain inference methods for accuracy and robustness, in accordance with standard engineering practice is reviewed. Several studies were conducted to assess how well various methods perform on problems constructed so that correct answers are known, and to find out what underlying features of a problem cause strong or weak performance. For each method studied, situations were identified in which performance deteriorates dramatically. Over a broad range of problems, some well known methods do only about as well as a simple linear regression model, and often much worse than a simple independence probability model. The results indicate that some commercially available expert system shells should be used with caution, because the uncertain inference models that they implement can yield rather inaccurate results

Two Tongues, One Brain: Imaging Bilingual Speech Production

This review considers speaking in a second language from the perspective of motor-sensory control. Previous studies relating brain function to the prior acquisition of two or more languages (neurobilingualism) have investigated the differential demands made on linguistic representations and processes, and the role of domain-general cognitive control systems when speakers switch between languages. In contrast to the detailed discussions on these higher functions, typically articulation is considered only as an underspecified stage of simple motor output. The present review considers speaking in a second language in terms of the accompanying foreign accent, which places demands on the integration of motor and sensory discharges not encountered when articulating in the most fluent language. We consider why there has been so little emphasis on this aspect of bilingualism to date, before turning to the motor and sensory complexities involved in learning to speak a second language as an adult. This must involve retuning the neural circuits involved in the motor control of articulation, to enable rapid unfamiliar sequences of movements to be performed with the goal of approximating, as closely as possible, the speech of a native speaker. Accompanying changes in motor networks is experience-dependent plasticity in auditory and somatosensory cortices to integrate auditory memories of the target sounds, copies of feedforward commands from premotor and primary motor cortex and post-articulatory auditory and somatosensory feedback. Finally, we consider the implications of taking a motor-sensory perspective on speaking a second language, both pedagogical regarding non-native learners and clinical regarding speakers with neurological conditions such as dysarthria

Providing scientific visualisation for spatial data analysis: criteria and an assessment of SAGE

A consistent theme in recent work on developing exploratory spatial data analysis (ESDA) has been the importance attached to visualization techniques, particularly following the pioneering development of packages such as REGARD by Haslett et al (1990). The focus on visual techniques is often justified in two ways: (a) the power of modern graphical interfaces means that graphics is no longer a way of simply presenting results in the form of maps or graphs, but a tool for the extraction of information from data; (b)graphical, exploratory methods are felt to be more intuitive for non-specialists to use than methods of numerical spatial statistics enabling wider participation in the process of getting data insights. Despite the importance attached to visualisation techniques, very little work has been done to assess the effectiveness of techniques, either in the wider scientific visualisation community, or among those working with spatial data. This paper will describe a theoretical framework for developing visualisation tools for ESDA that incorporates a data model of what the analyst is looking for based on the concepts of "rough" and "smooth" elements of a data set and a theoretical scheme for assessing visual tools. The paper will include examples of appropriate tools and a commentary on the effectiveness of some existing package