A global count of the extreme poor in 2012: data issues,methodology and initial results

The 2014 release of a new set of purchasing power parity (PPP) conversion factors (PPPs) for 2011 has prompted a revision of the World Bank’s international poverty line. In revising the line, we have sought to minimize changes to the real purchasing power of the earlier $1.25 line (in 2005 PPPs), so as to preserve the integrity of the goalposts for international targets such as the Sustainable Development Goals (SDGs) and the World Bank’s twin goals – which were set with respect to that line. In particular, the new line was obtained by inflating the same fifteen national poverty lines – originally used by Ravallion et al. (World Bank Econ. Rev. 23(2): 163–184 2009) to construct the $1.25 line – to 2011 prices in local currency units, and then converting them to US dollars using 2011 PPP conversion factors. With a small approximation, this procedure yields a new international poverty line of $1.90 per person per day. In combination with other changes described in the paper, this revision leads to relatively small changes in global poverty incidence for 2011: from 14.5 % using the old method to 14.1 % using the new method. In 2012, the new reference year for the global count, we find 12.7 % of the world’s population, or 897 million people, are living in extreme poverty. There are changes in the regional composition of poverty, but they are also relatively small. This paper documents methodological decisions taken in the process of updating both the poverty line and the consumption and income distributions at the country level, including issues of inter-temporal and spatial price adjustments. It also describes various caveats and limitations of the approach taken.     

Purchasing Power Parities of Currencies and Real Expenditures from the International Comparison Program: Recent Results and Uses

The International Comparison Program (ICP) is a worldwide statistical initiative designed to estimate purchasing power parities (PPPs) that can be used as currency converters to compare the performance of countries around the world, thereby providing in-depth views of the distribution of resources worldwide. The 2011 round of the ICP was leveraged on the successful outcome of the 2005 round that included 146 countries, introducing various methodological improvements. The summary report and results from the 2011 round were released in April 2014 and provided PPPs, price levels indices, and expenditures in PPP terms for the GDP and major aggregates for 199 participating countries. More detailed results were released in June 2014 and a final comprehensive report in October 2014. The final report provided a more in-depth analysis of volume and per capita indices. The results stirred a strong debate among the user community because of their finding that the world has become more equal than previously thought. The purpose of this paper is to provide an overview of the main results and findings of ICP 2011, its governance framework and partnership with the Eurostat-Organization for Economic Co-operation and Development (OECD) PPP program, and the major methodological innovations that were implemented. The paper reviews the major uses of the PPPs generated by the ICP 2011 and the Eurostat-OECD PPP program, and concludes with thoughts about the future of the ICP.     

Numerical solution of likelihood equations for a first-order response surface model for mixture paired comparisons

Summary A simple procedure for numerical solution of the likelihood equations for estimating the regression parameters of a first-order response surface model for the treatment parameters of mixture paired comparison experiments is developed. It is demonstrated that, for defined rotatable designs, those regression parameters are simple functions of the main effect parameters of a corresponding factorial model with no interactions. The maximum likelihood estimators of those main effect parameters, and hence of their corresponding regression parameters, are obtained through using procedures of treatment contrasts, factorial and iterations. A numerical example is given to illustrate applications of the procedures developed in this paper.     

On the wald,lagrangian multiplier and likelihood ratio tests when the information matrix is singular

Summary Modified formulas for the Wald and Lagrangian multiplier statistics are introduced and considered together with the likelihood ratio statistics for testing a typical null hypothesisH ₀ stated in terms of equality constraints. It is demonstrated, subject to known standard regularity conditions, that each of these statistics and the known Wald statistic has the asymptotic chi-square distribution with degrees of freedom equal to the number of equality constraints specified byH ₀ whether the information matrix is singular or nonsingular. The results of this paper include a generalization of the results of Sively (1959) concerning the equivalence of the Wald, Lagrange multiplier and likelihood ratio tests to the case of singular information matrices.     

Asymptotic properties of LS and QML estimators for a class of nonlinear GARCH processes

We consider estimation of a class of power-transformed threshold GARCH models. When the power of the transformation is known, the asymptotic properties of the quasi-maximum likelihood estimator (QMLE) are established under mild conditions. Two sequences of least-squares estimators are also considered in the pure ARCH case, and it is shown that they can be asymptotically more accurate than the QMLE for certain power transformations. In the case where the power of the transformation has to be estimated, the asymptotic properties of the QMLE are proven under the assumption that the noise has a density. The finite-sample properties of the proposed estimators are studied by simulation.     

The effect of computer intervention and task structure on bargaining outcome

This paper reports on a study that examined the impact of computer presentation of suggested solutions during negotiation, in bargaining situations that can be characterized as integrative or distributive. It was found that in the integrative task, the bargainers achieved higher joint outcomes when presented with suggestions. They had a more negative perception of the negotiation atmosphere, however. In the distributive task, the suggestions did not help achieve joint gains, but it lessened negative attitudes of the bargainers. Bargainers who received suggestions felt both they and their partner had been somewhat more flexible, cooperative, considerate, and less suspicious. Thus, regardless of negotiation situation, the suggestions resulted in some benefit to the negotiators.     

Assigning Students to Groups: A Multi-Criteria Decision Support System Approach*

MCADSS is a multi-criteria allocation decision support system for assisting in the task of allocating students to groups. Based on multiple criteria, MCADSS's goal is to maximize the diversity of members within groups, while minimizing the average differences between groups. The project may be viewed from several perspectives: as a multi-criteria decision-making problem, as a “reverse'’clustering problem, or as a personnel assignment problem. The system is currently being used to allocate M.B.A. students into sections and study teams at The European Institute of Business Administration (INSEAD). This paper describes the rationale for MCADSS, design criteria, system methodology, and application results. It also suggests how this approach could be used for further applications.