Influential observations in principal component analysis:a case study

A number of results have been derived recently concerning the influence of individual observations in a principal component analysis. Some of these results, particularly those based on the correlation matrix, are applied to data consisting of seven anatomical measurements on students. The data have a correlation structure which is fairly typical of many found in allometry. This case study shows that theoretical influence functions often provide good estimates of the actual changes observed when individual observations are deleted from a principal component analysis. Different observations may be influential for different aspects of the principal component analysis (coefficients, variances and scores of principal components); these differences, and the distinction between outlying and influential observations are discussed in the context of the case study. A number of other complications, such as switching and rotation of principal components when an observation is deleted, are also illustrated.     

Dependent masking and system life data analysis: Bayesian inference for two-component systems

Data from field operations of a system is often used to estimate the reliability of components. Under ideal circumstances, this system field data contains the time to failure along with information on the exact component responsible for the system failure. However, in many cases, the exact component causing the failure of the system cannot be identified, and is considered to be masked. Previously developed models for estimation of component reliability from masked system life data have been based upon the assumption that masking occurs independently of the true cause of system failure. In this paper we develop a Bayesian methodology for estimating component reliabilities from masked system life data when the probability of masking is dependent upon the true cause of system failure. The Bayesian approach is illustrated for the case of a two-component system of exponentially distributed components.     

Rupert B. Vance on Population

Rupert B. Vance, a distinguished sociologist, was a true Renaissance man whose writings spanned a variety of disciplines and touched on many issues of public as well as professional interest. As is typical of such scholars, his writings are published in a broad range of books, journals, newspapers, and other outlets. Reed and Singal (1982) brought together a selection of his writings on the South as a region, but his works in other areas have not been synthesized. The effort here is to assess his contributions to the field of population. Although no great ideas in population analysis are associated with his name, a review of his publications shows that he often was ahead of his time in dealing with issues and his influence on the field can be profoundly felt.     

The impact of legislator attributes on interest-group campaign contributions

Legislators possess political assets that economic interest groups may find valuable in pursuing their goals. This paper examines the effect these legislative assets have on the campaign contributions made by two large and easily identifiable interest groups: corporations and labor unions. Committee assignment, voting record, and electoral security are significant predictors of both corporate and union contributions to House incumbents, while party affiliation and years in office also influence the behavior of union political action committees.     

The influence of unconscious fantasy process in addictions and relapse

This discussion reaffirms the connection between addiction and underlying unconscious fantasy process. It suggests that unconscious fantasies play a determining role in persisting patterns of substance abuse and addiction. Within this context, addiction is understood both as a derivative of thepersistence of these unresolved fantasies and an inadequate compromise formation. It suggests that relapse is a manifestation of the episodic reassertion and influence of these powerful fantasies. Consequently, successful treatment requires the working through of the underlying fantasy process and the establishment of healthier compromise formations.