Irregular Immigration,Labour Market and Enforcement at the US‐Mexico Border. Evidence from a Time‐Series Analysis (1963–2014)

This article provides evidence on irregular immigration to the US from Mexico in the years 1963–2014. It aims to answer to two questions. The first is: how much is irregular immigration responsive to changes in the US labour market? Compared with legal immigration, irregular immigration seems to be more sensitive to short‐run economic cycles as it is not directly regulated by the policies of the destination country. Second, what effect does border enforcement have on irregular immigration? One of the proposals of the recent bill is the construction of a double layer fence on the Southern border. We do not know, however, to what extent a further increase in border security will prevent irregular immigration and at which economic cost. The contribution of this article is dual: first, it provides empirical evidence on irregular immigration to the US Second, it provides evidence about the effect of US border policies on irregular immigration.     

Prediction of accrual closure date in multi-center clinical trials with discrete-time Poisson process models

In a phase III multi‐center cancer clinical trial or a large public health study, sample size is predetermined to achieve desired power, and study participants are enrolled from tens or hundreds of participating institutions. As the accrual is closing to the target size, the coordinating data center needs to project the accrual closure date on the basis of the observed accrual pattern and notify the participating sites several weeks in advance. In the past, projections were simply based on some crude assessment, and conservative measures were incorporated in order to achieve the target accrual size. This approach often resulted in excessive accrual size and subsequently unnecessary financial burden on the study sponsors. Here we proposed a discrete‐time Poisson process‐based method to estimate the accrual rate at time of projection and subsequently the trial closure date. To ensure that target size would be reached with high confidence, we also proposed a conservative method for the closure date projection. The proposed method was illustrated through the analysis of the accrual data of the National Surgical Adjuvant Breast and Bowel Project trial B‐38. The results showed that application of the proposed method could help to save considerable amount of expenditure in patient management without compromising the accrual goal in multi‐center clinical trials. Copyright © 2012 John Wiley & Sons, Ltd.     

Measuring Citizen Satisfaction with Aspects of Public Services from a Local Authority and Determining Their Importance: A Case Study

The measurement of service quality is a theme of great importance to service providers, particularly public agencies. Over the years their role has been changing by providing more and more high quality services, away from basic ones. In this paper the service quality of a local government is analyzed through the measurement of customer satisfaction. The analysis, based on a questionnaire survey, identified and classified the most essential factors that make up the customer satisfaction with the services provided by the Demographic Department of Gioia del Colle, a town in southern Italy.

Firm-specific human capital, job matching, and turnover: evidence from major league baseball, 1900–1992

The two dominant labor market turnover hypotheses, the firm-specific human capital model (FSHCM) and the job-matching model, suggest different patterns of player mobility in major league baseball. The matching hypothesis predicts greater mobility of players in positions that require substantial team production. A better match may offer large productivity gains. Alternately, the FSHCM predicts players in positions requiring the greatest amount of teamwork will benefit from specific knowledge, making them less likely to change teams. We examine the frequency distribution of trades by player position from 1900–1992 and find the FSHCM provides the best explanation for turnover in this industry.     

Multistage Modeling of Lung Cancer Mortality Among Arsenic-Exposed Copper-Smelter Workers

Multistage modeling incorporating a time-dependent exposure pattern is applied to lung cancer mortality data obtained from a cohort of 2802 arsenic-exposed copper-smelter workers who worked 1 or more years during the period 1940-1964 at a copper smelter at Tacoma, Washington. The workers were followed for death through 1976. There were 100 deaths due to lung cancer during the follow-up period. Exposures to air arsenic levels measured in micrograms/m3 were estimated from departmental air arsenic and workers urinary arsenic measurements. Relationships of different temporal variables with excess death rates are examined to judge qualitatively the implications of the multistage cancer process. Analysis to date indicates a late stage effect of arsenic although an additional early stage effect cannot be ruled out.