Fitting the Lognormal Distribution to Surgical Procedure Times*

Minimum surgical times are positive and often large. The lognormal distribution has been proposed for modeling surgical data, and the three‐parameter form of the lognormal, which includes a location parameter, should be appropriate for surgical data. We studied the goodness‐of‐fit performance, as measured by the Shapiro‐Wilk p‐value, of three estimators of the location parameter for the lognormal distribution, using a large data set of surgical times. Alternative models considered included the normal distribution and the two‐parameter lognormal model, which sets the location parameter to zero. At least for samples with n > 30, data adequately fit by the normal had significantly smaller skewness than data not well fit by the normal, and data with larger relative minima (smallest order statistic divided by the mean) were better fit by a lognormal model. The rule “If the skewness of the data is greater than 0.35, use the three‐parameter lognormal with the location parameter estimate proposed by Muralidhar & Zanakis (1992), otherwise, use the two‐parameter model” works almost as well at specifying the lognormal model as more complex guidelines formulated by linear discriminant analysis and by tree induction.     

MEASUREMENT OF MULTIPLE SITES IN SERVICE FIRMS WITH DATA ENVELOPMENT ANALYSIS

Data envelopment analysis (dea) has become an increasingly popular method to measure performance for service firms with multiple sites. DEA is superior to many traditional methods for firms that have multiple goals. The promise of DEA is that the complex, multi-objective problem of performance measurement can be reduced to a single number. Unfortunately, the practice of DEA often belies the promise. Misconceptions concerning the purpose and implementation of DEA can cause DEA applications to be less than successful. Here, the technique is explained, and a guide to the implementation of DEA is proposed, utilizing DEA studies of retail bank branches.     

Threatening Places or Diverse Spaces: Divergent Constructions of Florida Puerto Ricans across Twitter and Newspaper Articles

This study examines constructions of Puerto Ricans across two different media forms: newspaper articles and Twitter. We use Poinciana, Florida, a Central Florida Puerto Rican enclave, as a means to examine these constructions. Because of the high concentration of Puerto Rican residents and unprecedented migration to the area, Poinciana is an ideal community to examine media constructions of a migrant group. Utilizing constructivist grounded theory, we analyze all published newspaper articles (1995–2016) and public Twitter posts (2009–2016) about Puerto Ricans in the region (N = 174). We find newspaper articles construct mostly benign views of Puerto Ricans, reflecting “Happy Talk” diversity discourse, while Twitter constructions present more negative portrayals, generally relating to population size, and often reflecting a racist ideology reminiscent of the Latino Threat Narrative. We conclude by detailing the significance of divergent constructions across media forms during a period of heightened migration, and how the type of media consumed by Puerto Ricans in this community known as “Little Puerto Rico” is likely to influence their perceived level of societal acceptance.     

On the Run Length of a State-Space Control Chart for Multivariate Autocorrelated Data

The literature on statistical process control (SPC) describes the negative effects of autocorrelation in terms of the increase in false alarms. This has been treated by the individual modeling of each series or the application of VAR models. In the former case, the analysis of the cross correlation structure between the variables is altered. In the latter, if the cross correlation is not strong, the filtering process may modify the weakest relations. In order to improve these aspects, state-space models have been introduced in multivariate statistical process control (MSPC). This article presents a proposal for building a control chart for innovations, estimating its average run length to highlight its advantages over the VAR approach mentioned above.     

Powerlessness y Participacion Politica Convencional

Este artículo presenta una aproximación a la participación política convencional desde una perspectiva psicosocial. Partiendo de una crítica al confusionismo y escaso valor predictivo proporcionado por las variables sociodemográficas, se analiza la contribución del constructo de «powerlessness» a la explicación de la conducta de voto. Se discute la multidimensionalidad del constructo y sus posibilidades para la comprensión de la problemática de la abstención electoral.     

Influence of Age on Transracial Foster Adoptions and Its Relation to Ethnic Identity Development

In the United States, ethnic minorities are disproportionately represented in the foster care system and underrepresented among potential adoptive parents. The need to find permanent homes for foster children has led to an increase in the controversial practice of transracial adoption (TRA), wherein ethnic minority children are placed in adoptive homes with Caucasian parents. While many child welfare scholars and dependency stakeholders support TRA as a positive alternative to foster care, others are concerned that such adoptions may inhibit the ethnic identity development of transracially adopted children. This article documents the large number of ethnic minority children who are adopted through TRA prior to the onset of ethnic identification and how age influences which children are adopted out of foster care. The findings indicate that young ethnic minorities are significantly more likely to be adopted through TRA compared to older children, an effect especially prominent among African Americans. Implications for the child welfare system are discussed.     

The relational costs of crossing class lines

How do low socioeconomic status students navigate cross-class interactions in extremely unequal contexts? Previous research has described the high costs of college integration for underprivileged students, which in turn, negatively impact academic performance and general wellbeing. These studies tend to concentrate on cultural capital costs, such as catching up with assumed middle-class or elite capital and dealing with two worlds. Less has been said about social capital costs, the costs of making friends, especially more privileged friends. Through 61 in-depth interviews with various types of students as part of a broader ethnographic fieldwork, this article analyses the experiences of low-income scholarship holders in an elite institution in a very unequal society, Colombia. Rather than isolating themselves or resorting to safe homophilic relations, they faced their new elite environment engaging with the hidden relational cost of making friends with more affluent students. In so doing, they had to overcome fears and experiences of discrimination and micro-aggressions, as well as cultural and economic capital barriers, and employed either camouflaging or disclosure strategies, sometimes becoming culturally and socially omnivorous. Symbolic belonging to the institution and the acquisition of middle-class cultural capital were among the benefits that made overcoming the costs worthy. Our results shed light on what institutions can do to reduce the costs for underprivileged students and, theoretically, unveil an important mechanism and barrier for social mobility: building cross-class ties.