Principal component and correspondence analysis of compositional data: some similarities

Principal component and correspondence analysis can both be used as exploratory methods for representing multivariate data in two dimensions. Circumstances under which the, possibly inappropriate, application of principal components to untransformed compositional data approximates to a correspondence analysis of the raw data are noted. Aitchison (1986) has proposed a method for the principal component analysis of compositional data involving transformation of the raw data. It is shown how this can be approximated by a correspondence analysis of appropriately transformed data. The latter approach may be preferable when there are zeroes in the data.     

Exponential Family Models for sampled and census Network data

Much progress has been made on the development of statistical methods for network analysis in the past ten years, building on the general class of exponential family random graph (ERG) network models first introduced by Holland and Leinhardt (1981) . Recent examples include models for Markov graphs, "p*" models, and actor‐oriented models. For empirical application, these ERG models take a logistic form, and require the equivalent of a network census: data on all dyads within the network. In a largely separate stream of research, conditional log‐linear (CLL) models have been adapted for analyzing locally sampled ("egocentric") network data. While the general relation between log‐linear and logistic models is well known and has been exploited in the case of a priori blockmodels for networks, the relation for the CLL models is different due to the treatment of absent ties. For fully saturated tie independence models, CLL and ERG are equivalent and related via Bayes' rule. For other tie independence models, the two do not yield equivalent predicted values, but we show that in practice the differences are unlikely to be large. The alternate conditioning in the two models sheds light on the relationship between local and complete network data, and the role that models can play in bridging the gap between them.     

A Holland Perspective on the U.S. Workforce From 1960 to 2000

The authors analyze civilian occupations and employment data collected by the U.S. Census Bureau in 1960, 1970, 1980, 1990, and 2000 with respect to 6 kinds of work (Holland's RIASEC [Realistic, Investigative, Artistic, Social, Enterprising, Conventional] classification), employment, and gender. For the 1990 and 2000 censuses, kinds of work, gender, and income are analyzed, and for the 2000 census, kinds of work, age, and gender are examined. Past employment trends developed from census data are further analyzed with respect to Bureau of Labor Statistics employment projections through 2012. Implications for further research, employment policy, and career services are offered.     

The Permeable Border: Examining Responses to North American Integration in Video Art

Abstract

In this essay, I suggest that artistic production provides valuable insights into the nature of the Canada-US border during the late-twentieth century when significant changes were occurring to dominant understandings of Canada in relation to North America. Focusing on the medium of video art, I trace the sustained engagement of Canadian contemporary artists to respond to and comment on the move towards continental integration through free trade. I contextualize my discussion in relation to trade developments that opened Canada’s border with the US, such as the 1989 implementation of the Canada-US Free Trade Agreement. This agreement, along with the later North American Free Trade Agreement, led to increasing continental integration at the end of the twentieth century, as well as hope for hemispheric integration with the subsequent negotiations towards the Free Trade Area of the Americas. With attention to works by Lisa Steele and Kim Tomczak, Eva Manly, and Clive Robertson, I foreground cultural contributions to redefining the Canada-US borderlands. Here, I chart the artists’ intention to echo narratives of the border’s porousness and address the power dynamics between the Canadian state and its trade partners. Examining themes of cultural imperialism, colonialism, and national identity, I point to the importance of cultural production in assessing the borderlands and, more broadly, histories of free trade in North America.     

Domestic Violence Service Providers’ Needs and Perceptions of Technology: A Qualitative Study

There is growing recognition of the need to better understand the intersections between the work of domestic violence service providers and technology. Professionals who work with clients impacted by domestic violence are increasingly using technologies across different aspects of their work, including communicating with other professionals and seeking information and resources via the Internet. The current study used qualitative data from two sources—individual interviews and two focus groups—to learn about domestic violence service providers’ needs and perceptions related to technology use. The results provide insights about technologies used currently, expected benefits of future technological advances, barriers to using technology, and participants’ self-rated levels of comfort with technology.