The distribution of standard deviations applied to high throughput screening

High throughput screening (HTS) assesses compound libraries for “activity” using target assays. A subset of HTS data contains a large number of sample measurements replicated a small number of times providing an opportunity to introduce the distribution of standard deviations (DSD). Applying the DSD to some HTS data sets revealed signs of bias in some of the data and discovered a sub-population of compounds exhibiting high variability which may be difficult to screen. In the data examined, 21% of 1189 such compounds were pan-assay interference compounds. This proportion reached 57% for the most closely related compounds within the sub-population. Using the DSD, large HTS data sets can be modelled in many cases as two distributions: a large group of nearly normally distributed “inactive” compounds and a residual distribution of “active” compounds. The latter were not normally distributed, overlapped inactive distributions – on both sides –, and were larger than typically assumed. As such, a large number of compounds are being misclassified as “inactive” or are invisible to current methods which could become the next generation of drugs. Although applied here to HTS, it is applicable to data sets with a large number of samples measured a small number of times

JOURNAL OF POLICY MODELING

Sociopolitical instability is considered detrimental to long-run growth. This paper presents the results of a thorough investigation of the effects of sociopolitical instability on growth, for a panel of countries over a 30-year period. Consistent with the existing literature, weak relationships between sociopolitical instability and growth are found. Political violence has the greatest adverse effects on growth. Also, the impact of sociopolitical instability is greater in countries with high levels of development and democracy. Robustness tests indicate little evidence of simultaneity problems, but estimation results are very sensitive to extreme observations, and to a lesser extent, parameter heterogeneity. The results suggest that one of the best ways to improve the lot of the poorest countries is the prevention and/or termination of violence and war. (c) 2005 Society for Policy Modeling. Published by Elsevier Inc. All rights reserved

WORLD DEVELOPMENT

The International Monetary Fund and the World Bank, frequently, and often repeatedly, extend loans to developing nations. These loans have been blamed for generating adverse economic outcomes. The growth impact of Fund and Bank loan programs is assessed using an empirical growth model that controls for other determinants of growth. A unique feature of this study is the use of the value of loans rather than the number of programs. The estimates indicate that Bank lending stimulates growth in some cases, primarily by increasing public investment. Fund lending is either neutral or detrimental to growth. The channel for this effect is a negative impact of Fund lending on public as well as private investment. (c) 2004 Elsevier Ltd. All rights reserved

ECONOMIC MODELLING

Analysis of the factors determining rates of economic growth has found that country-specific characteristics have important effects on growth performance. Empirical evidence to date suggests that maintenance of the rule of law promotes growth, while adopting democratic institutions does not appear to improve growth performance. We find that these conclusions are very sensitive to sample selection and to estimation technique. When an identical sample of countries is used, we find that countries with democratic institutions do enjoy superior growth performance. The relationship between growth and democratic institutions is also sensitive to the estimation technique used. Estimates using instrumental variable techniques suggest that democratic institutions do experience better growth performance. These results are especially relevant for developing nations. (c) 2006 Elsevier B.V. All rights reserved

EMERGING MARKETS FINANCE AND TRADE

New empirical estimates of the effects of capital restrictions on growth support capital account liberalization, especially for developed countries. Capital restrictions reduce the benefits of foreign direct investment (FDl) on growth in developing countries. Estimation results for long-term capital flows demonstrate that countries with higher flows grow faster, challenging the belief that countries must attain a threshold level of development or human capital to benefit from capital inflows. Moreover, findings show that trade with developed countries and FDl inflows are substitutes in developing countries. Overall, the results support capital account liberalization in developed and developing countries