Strengthening Financial Markets for the Poor

Books reviewed in this article: Martin Brownbridge and Charles Harvey, Banking in Africa: the Impact of Financial Sector Reform since Independence Machiko Nissanke and Ernest Aryeetey, Financial Integration and Development: Liberalisation and Reform in sub-Saharan Africa Geoffrey D. Wood and Iffath A. Sharif (eds.), Who Needs Credit? Poverty and Finance in Bangladesh     

Efficient use of exact samples

Propp and Wilson (Random Structures and Algorithms (1996) 9: 223–252, Journal of Algorithms (1998) 27: 170–217) described a protocol called coupling from the past (CFTP) for exact sampling from the steady-state distribution of a Markov chain Monte Carlo (MCMC) process. In it a past time is identified from which the paths of coupled Markov chains starting at every possible state would have coalesced into a single value by the present time; this value is then a sample from the steady-state distribution.Unfortunately, producing an exact sample typically requires a large computational effort. We consider the question of how to make efficient use of the sample values that are generated. In particular, we make use of regeneration events (cf. Mykland et al. Journal of the American Statistical Association (1995) 90: 233–241) to aid in the analysis of MCMC runs. In a regeneration event, the chain is in a fixed reference distribution– this allows the chain to be broken up into a series of tours which are independent, or nearly so (though they do not represent draws from the true stationary distribution).In this paper we consider using the CFTP and related algorithms to create tours. In some cases their elements are exactly in the stationary distribution; their length may be fixed or random. This allows us to combine the precision of exact sampling with the efficiency of using entire tours.Several algorithms and estimators are proposed and analysed.     

Cleaning up their act: The effects of marriage and cohabitation on licit and illicit drug use

We use data from the National Longitudinal Survey of Youth to estimate changes in binge drinking, marijuana use, and cigarette smoking surrounding young adults' first experiences of cohabitation and marriage. Both marriage and cohabitation are accompanied by decreases in some risk behaviors, but reductions surrounding marriage are larger and most consistent, particularly for men. Binge drinking and marijuana use respond to these events, especially marriage, but smoking does not.     

Shaking things up or business as usual? The influence of female corporate executives and board of directors on women’s managerial representation

Previous theory and research suggests that workplace gender composition at the highest organizational levels should play a crucial role in reducing gender linked inequalities in the workplace. In this article, we examine how the presence of women in top corporate positions influences female managerial representation at the establishment-level. Using a unique multi-level dataset of 5679 establishments nested within 81 Fortune 1000 corporations, we find that having more women on corporate boards, but not in executive positions, at the firm-level is associated with greater female managerial representation at the establishment-level. The results also show that women are more likely to be in management positions when employed in young, large, and managerially intensive workplaces, as well as those with a larger percentage of female non-managers. Implications for future research and policy implementation are discussed.     

An evaluation of likelihood-based bandwidth selectors for spatial and spatiotemporal kernel estimates

Spatial point pattern data sets are commonplace in a variety of different research disciplines. The use of kernel methods to smooth such data is a flexible way to explore spatial trends and make inference about underlying processes without, or perhaps prior to, the design and fitting of more intricate semiparametric or parametric models to quantify specific effects. The long-standing issue of ‘optimal’ data-driven bandwidth selection is complicated in these settings by issues such as high heterogeneity in observed patterns and the need to consider edge correction factors. We scrutinize bandwidth selectors built on leave-one-out cross-validation approximation to likelihood functions. A key outcome relates to previously unconsidered adaptive smoothing regimens for spatiotemporal density and multitype conditional probability surface estimation, whereby we propose a novel simultaneous pilot-global selection strategy. Motivated by applications in epidemiology, the results of both simulated and real-world analyses suggest this strategy to be largely preferable to classical fixed-bandwidth estimation for such data.     

Reliability and Validity of the IPAQ-L in a Sample of Hong Kong Urban Older Adults: Does Neighborhood of Residence Matter?

This study examined reliability and validity of the Chinese version of the International Physical Activity Questionnaire-Long Form (IPAQ-LC) in Chinese seniors, including moderating effects of neighborhood walkability and socioeconomic status (SES) on reliability and validity. The IPAQ-LC was interviewer-administered (n = 96), accelerometer and 7-day walk-diary data were collected (n = 94), and the IPAC-LC was readministered (N = 92). Acceptable reliability was found for all measures of physical activity (PA) overall and across different types of neighborhood. Participants from highly walkable neighborhoods were more reliable at estimating walking for transport. Participants from low-SES areas were less reliable at estimating leisure-time PA and sitting but more reliable at estimating transport-related walking. IPAQ-LC walking was significantly related to light- but not moderate-intensity accelerometry-based PA. It was moderately to strongly related to a 7-day diary of walking. The data imply slow-paced walking, probably due to age, climate, and terrain. The findings suggest that the IPAQ-LC's reliability and validity are acceptable in Chinese seniors.