Book review

How to Conduct Self‐administered and Mail Surveys, L. B. Bourque and E. P. Fielder, London, Sage Publications, 1995, 223 pp, £17.50     

Extending dual multiple factor analysis to categorical tables

This paper describes a proposal for the extension of the dual multiple factor analysis (DMFA) method developed by Lê and Pagès 15 to the analysis of categorical tables in which the same set of variables is measured on different sets of individuals. The extension of DMFA is based on the transformation of categorical variables into properly weighted indicator variables, in a way analogous to that used in the multiple factor analysis of categorical variables. The DMFA of categorical variables enables visual comparison of the association structures between categories over the sample as a whole and in the various subsamples (sets of individuals). For each category, DMFA allows us to obtain its global (considering all the individuals) and partial (considering each set of individuals) coordinates in a factor space. This visual analysis allows us to compare the set of individuals to identify their similarities and differences. The suitability of the technique is illustrated through two applications: one using simulated data for two groups of individuals with very different association structures and the other using real data from a voting intention survey in which some respondents were interviewed by telephone and others face to face. The results indicate that the two data collection methods, while similar, are not entirely equivalent.     

Renaissance of a rural artifact in a city with a million people: biodiversity responses to an agro-forestry restoration in a large urban traditional fruit orchard

The rural landscapes surrounding large cities are rapidly becoming incorporated into the urban environment. The most conspicuous changes involve green spaces, such as former agro-forestry systems like fruit orchards. In this paper, we assess the influence on biodiversity of restoring a large urban traditional fruit orchard as reflected by six selected taxa: plants, lichens, butterflies, beetles, orthopteroids and birds. The study was performed in Prague, which is the capital city of the Czech Republic and has more than a million inhabitants. We studied the effect of orchard renewal in 45 patches (15 for birds and 30 for other taxa). The majority of taxa responded positively to the restoration. The restoration had a significant positive effect on the species richness of lichens, butterflies and beetles. All taxa showed significantly altered species compositions, and the number of red-listed species increased. Orchards have a high potential for multi-functional use. Orchards are productive agro-forestry systems and host numerous possible human activities. Therefore, orchard restoration also has a social aspect. Moreover, our research in this artificial ecosystem revealed that its restoration increased the biodiversity and conservation potential of the associated areas.

     

India's structural transformation and role in the world economy

This paper employs (1) a three-sector structuralist model of development with informal and formal activities and (2) a global one-sector model with demand determined outputs and bargained distribution to investigate whether India's growth performance can be sustained, where the country might face constraints to growth, and how India's growth matters in the global economy.     

Analysis of 0 to 10-point response scales using factorial methods: a new perspective

This paper analyses the implications of using survey response scales with 10 or more categories which are often analysed using factorial techniques such as principal components analysis. Although it is the type of metric that determines the choice of this method of analysis, these scales, despite being considered metric, lack some metric properties, such that a score of 10 in a satisfaction survey, for example, does not represent twice the satisfaction of a score of 5. Their ordinal nature also means they cannot be treated as purely categorical. Thus, having both metric and categorical properties, they allow the use of different factor analysis techniques. The second objective is to apply different factorial techniques to a given test item in order to detect potential differences in the analytical information obtained by each method. Finally, we will discuss their relative advantages and disadvantages for use with this type of survey question.     

Comparing point and interval estimates in the bivariate <Emphasis Type="Italic">t</Emphasis>-copula model with application to financial data

The paper considers joint maximum likelihood (ML) and semiparametric (SP) estimation of copula parameters in a bivariate t-copula. Analytical expressions for the asymptotic covariance matrix involving integrals over special functions are derived, which can be evaluated numerically. These direct evaluations of the Fisher information matrix are compared to Hessian evaluations based on numerical differentiation in a simulation study showing a satisfactory performance of the computationally less demanding Hessian evaluations. Individual asymptotic confidence intervals for the t-copula parameters and the corresponding tail dependence coefficient are derived. For two financial datasets these confidence intervals are calculated using both direct evaluation of the Fisher information and numerical evaluation of the Hessian matrix. These confidence intervals are compared to parametric and nonparametric BCA bootstrap intervals based on ML and SP estimation, respectively, showing a preference for asymptotic confidence intervals based on numerical Hessian evaluations.     

Oral Hygiene and Lifestyle Correlates Among New Undergraduate University Students in Lebanon

Abstract

Little is known about Lebanese college students' oral hygiene and the factors associated with how often they brush their teeth. The authors used a structured questionnaire to investigate these issues in a sample of 954 new students at the American University of Beirut in fall 1998. The results indicated poor flossing habits and unfavorable dietary habits among the group. Moreover, using logistic regression analysis, they found that variables such as gender, father's education, exercise, and dietary habits, were significantly correlated with the how frequently the students brushed their teeth. Appropriate promotional activities to improve flossing and dietary habits associated with better oral hygiene are recommended. In addition, the authors call for further research to elaborate on the deficiencies in oral health practices and explore a wider variety of lifestyle behaviors and their correlation.