On the analysis of long-term experiments

Summary.  Long-term experiments are commonly used tools in agronomy, soil science and other disciplines for comparing the effects of different treatment regimes over an extended length of time. Periodic measurements, typically annual, are taken on experimental units and are often analysed by using customary tools and models for repeated measures. These models contain nothing that accounts for the random environmental variations that typically affect all experimental units simultaneously and can alter treatment effects. This added variability can dominate that from all other sources and can adversely influence the results of a statistical analysis and interfere with its interpretation. The effect that this has on the standard repeated measures analysis is quantified by using an alternative model that allows for random variations over time. This model, however, is not useful for analysis because the random effects are confounded with fixed effects that are already in the repeated measures model. Possible solutions are reviewed and recommendations are made for improving statistical analysis and interpretation in the presence of these extra random variations.     

Is Preventing Coerced Repatriation Ethical and Possible? The Case of NGO Repatriation of South Sudanese in Israel

“Voluntary repatriation” to a country of origin may be necessary to restore refugees' rights, when only a country of origin will provide rights associated with citizenship. Yet, if refugees are returning because they do not have access to basic rights in a host country, their return is not voluntary according to UNHCR guidelines (1996). There is a tension between facilitating repatriation to restore rights, and ensuring that repatriation is voluntary. This article will first draw on arguments from moral philosophy to suggest an alternative policy to current UNHCR guidelines. Following this normative analysis, the article hypothesizes that, on an empirical level, a repatriation policy that attempts to only facilitate repatriation that is not coerced, out of concern for voluntariness alone, may fail both to prevent coerced returns and to restore right through repatriation. This hypothesis was then tested in the case of South Sudanese repatriation from Israel between 2009‐2012.     

Variability in the Inter‐group Attitudes of White Children: What We Can Learn from Their Ethnic Identity Labels

The current study examined the ethnic identity of White (N = 120), Latino (N = 87), and African‐American (N = 65) children and early adolescents (aged = 9–14 years), with an emphasis on whether the specific ethnic label White children used to describe themselves might reflect differences in their inter‐group attitudes and whether those differences mirror group differences between White children and children in ethnic minority groups. Results indicated that White children who identified with a minority label (i.e., White biracial, hyphenated American, ethnic/cultural/religious label) had more positive ethnic identities, were more aware of discrimination, and were less likely to show biases in their perceived similarity to in‐group and out‐group peers than youth who identified as White or American. In many instances, White children who identified with a minority label did not differ from ethnic minority youth. In addition, although all participants were more positive about their ethnic in‐group than out‐groups, children who identified their ethnicity as American were less positive about out‐groups relative to other children. Taken together, the findings indicate that children's self‐chosen ethnic identity is as important as their ascribed ethnic or racial identity in predicting their inter‐group attitudes.     

Understanding the mobility chances of children from working-class backgrounds in Britain: How important are cognitive ability and locus of control?

Research in social stratification has shown that children from working-class backgrounds tend to obtain substantially lower levels of educational attainment and lower labor market positions than children from higher social class backgrounds. However, we still know relatively little about the micro-level processes that account for this empirical regularity. Our study examines the roles of two individual-level characteristics—cognitive ability and locus of control—in mediating the effect of individuals’ parental class background on their educational attainment and social class position in Britain. We find that cognitive ability mediates only about 35% of the total parental class effect on educational attainment and only about 20% of the total parental class effect on respondents’ social class position, net of their educational attainment. These findings contradict existing claims that differences in the life chances of children from different social class backgrounds are largely due to differences in cognitive ability. Moreover, we find that although individuals’ locus of control plays some role in mediating the parental class effect, its role is substantially smaller than the mediating role of cognitive ability. We measure individuals’ social class positions at different points in their careers—at labor market entry and at occupational maturity—and find that the mediating roles of cognitive ability and locus of control are remarkably stable across individuals’ working lives.