Optical output enhances flowmeter accuracy

Magnetic flowmeter with a direct-coupled optical output increases accuracy and operates independently of other system inputs. The design includes simple external adjustment and signal amplitude control

Intersectoral Labor Mobility and the Growth of the Service Sector

One of the most striking changes in the U.S. economy over the past 50 years has been the growth in the service sector. In 1950, 57 percent of workers were employed in the service sector, by 1970 that figure had risen to 63 percent and by 2000 to 75 percent. While service sector employment grew by 2.2 percent per year faster than employment in the goods sector between 1968 and 2000, the real hourly wage in the service sector grew only by 0.23 percent more per year over the same period. In this paper, we assess whether or not the essential constancy of the relative wage implies that individuals face small costs of switching sectors and quantify the relative importance of labor supply and demand factors in the growth of the service sector. We specify and estimate a two-sector growth model with idiosyncratic and aggregate shocks that allows us to address these empirical issues in a unified coherent framework. Our estimates imply that there are large mobility costs; output in both sectors would have been double their current levels if these mobility costs had been zero. In addition, we find that demand side factors, that is, technical change and movements in product and capital prices, were responsible for the growth of the service sector.labor mobility, service sector growth, labor market equilibrium

Accounting for Wage and Employment Changes in the U. S. from 1968-2000: A Dynamic Model of Labor Market Equilibrium

In this paper, we present a unified treatment of and explanation for the evolution of wages and employment in the U.S. over the last 30 years. Specifically, we account for the pattern of changes in wage inequality, for the increased relative wage and employment of women, for the emergence of the college wage premium and for the shift in employment from the goods to the service-producing sector. The underlying theory we adopt is neoclassical, a two-sector competitive labor market economy in which the supply of and demand for labor of heterogeneous skill determines spot market skill-rental prices. The empirical approach is structural. The model embeds many of the features that have been posited in the literature to have contributed to the changing U.S. wage and employment structure including skill-biased technical change, capital-skill complementarity, changes in relative product-market prices, changes in the productivity of labor in home production and demographics such as changing cohort size and fertility.Male-Female Wage Differential, Wage Inequality, College Wage Premium

Using a Social Experiment to Validate a Dynamic Behavioral Model of Child Schooling and Fertility: Assessing the Impact of a School Subsidy Program in Mexico

This paper studies the performance of a methodology that can be used to evaluate the impact of new policies that radically depart from existing ones. It uses data gathered from a randomized schooling subsidy experiment in Mexico (i) to estimate and validate a dynamic behavioral model of parental decisions about fertility and child schooling, (ii) to forecast long-term program impacts that extend beyond the life of the experiment, and (iii) to assess the impact of a variety of counterfactual policies. The behavioral model is estimated using data on families in the randomized-out control group and in the treatment group prior to the experiment, both of which did not receive any subsidy. Child wages provide a valuable source of variation in the data for identifying subsidy effects. Using the estimated model, we predict the effects of school subsidies according to the schedule that was implemented under the Mexican PROGRESA program.schooling, child labor, fertility, structural estimation, social experiments

Accounting for Wage and Employment Changes in the U.S. from 1968-2000: A Dynamic Model of Labor Market Equilibrium

This paper presents a unified treatment of and explanation for the evolution of wages and employment in the U.S. over the last 30 years. Specifically, we account for the pattern of changes in wage inequality, for the increased relative wage and employment of women, for the emergence of the college wage premium and for the shift in employment from the goods to the service-producing sector. The underlying theory we adopt is neoclassical, a two-sector competitive labor market economy in which the supply of and demand for labor of heterogeneous skill determines spot market skill-rental prices. The empirical approach is structural. The model embeds many of the features that have been posited in the literature to have contributed to the changing U.S. wage and employment structure including skill-biased technical change, capital-skill complementarity, changes in relative product-market prices, changes in the productivity of labor in home production and demographics such as changing cohort size and fertility.gender wage differential, college wage premium, sectoral changes

The Transition from School to Jail: Youth Crime and High School Completion Among Black Males, Second Version

In this paper, we study the relationship among schooling, youth employment and youth crime. The framework, a multinomial discrete choice vector autoregression, provides a comprehensive analysis of the dynamic interactions among a youth’s schooling, work and crime decisions and arrest and incarceration outcomes. We allow for observable initial conditions, unobserved heterogeneity, measurement error and missing data. We use data from the NLSY97 on black male youths starting from age 14. The estimates indicate important roles both for heterogeneity in initial conditions and for stochastic events that arise during one’s youth in determining outcomes as young adults.crime, schooling, work, VAR

The Transition from School to Jail: Youth Crime and High School Completion Among Black Males

In this paper, we propose a new approach to the empirical study of the relationships among schooling, youth employment and youth crime which provides a comprehensive analysis of the dynamic interactions among these choices and exposure to the criminal justice system. The empirical framework takes the form of a multinomial discrete choice vector autoregression of a youth’s schooling, work and crime decisions as well as arrest and incarceration outcomes. We allow for observable initial conditions, unobserved heterogeneity, the possibility of measurement error and for missing data. We use data from the NLSY97 on black male youths starting from age 14. The estimates indicate an important role for heterogeneity in initial conditions. We also find that stochastic events that arise during one’s youth can be important in determining outcomes as young adults.crime, schooling, work, VAR

Exploring the Usefulness of a Non-Random Holdout Sample for Model Validation: Welfare Effects on Female Behavior

Opportunities for external validation of behavioral models in the social sciences that are based on randomized social experiments or on large regime shifts, that can be treated as experiments for the purpose of model validation, are extremely rare. In this paper, we consider an alternative approach, namely mimicking the essential element of regime change by non-randomly holding out from estimation a portion of the sample that faces a significantly different policy regime. The non-random holdout sample is used for model validation/selection. We illustrate the non-random holdout sample approach to model validation in the context of a model of welfare program participation. The policy heterogeneity that we exploit to generate a non-random holdout sample takes advantage of the wide variation across states that has existed in welfare policy.Model validation, Hold-out sample, Public welfare

Specific Experience, Household Structure and Intergenerational Transfers: Farm Family Land and Labor Arrangements in Developing Countries

Land Economics/Use,