Malaria in Pacific populations: seen but not heard?

Most Pacific Island countries are located in the tropics, where there is an abundance of mosquitoes with the potential to carry debilitating or life-threatening vector-borne diseases. This article examines three Melanesian countries in which malaria is endemic—Papua New Guinea, Solomon Islands and Vanuatu—but the threat posed by the spread of malaria gives the issues a broader significance to the Pacific region. After discussing the spatial distribution and prevalence of malaria in the Pacific, the article examines a number of health interventions through which people have sought to control malaria. Although the disease was nearly eradicated in the Pacific in the 1970s, it is no longer in retreat. The article concludes by examining why there are still grounds for cautious optimism, and the challenges that Pacific Island countries face in reducing the impact of malaria on their populations. There is a need for prompt and concerted action on malaria at the national, regional and international levels if the public health concerns arising from the disease are to be adequately addressed.     

Business visits,knowledge diffusion and productivity

We investigate whether labor mobility can be a distinct source of growth by studying the productivity impact of business visits (BVs), vis-à-vis that of other well-known drivers of productivity enhancement. Our analysis uses an unbalanced panel—covering on average 16 sectors per year in ten countries during the period 1998–2011—which combines unique and novel data on BVs sourced from the US National Business Travel Association with Organization for Economic Cooperation and Development (OECD) data on R&D and capital formation. We find that mobility through BVs is an effective mechanism to improve productivity, being about half that obtained by investing in R&D. This relevant finding invites viewing short-term mobility as a strategic mechanism and prospective policy tool to overcome productivity slowdowns and foster economic growth.     

Effects of child support and welfare policies on nonmarital teenage childbearing and motherhood

This paper is an assessment of the impact of child support enforcement and welfare policies on nonmarital teenage childbearing and motherhood. We derive four hypotheses about the effects of policies on nonmarital teenage childbearing and motherhood. We propose that teenage motherhood and school enrollment are joint decisions for teenage girls. Based on individual trajectories during ages 12–19, our analysis uses an event history model for nonmarital teenage childbearing and a dynamic model of motherhood that is jointly determined with school enrollment. We find some evidence that child support policies indirectly reduce teen motherhood by increasing the probability of school enrollment, which, in turn, reduces the probability of teen motherhood. This finding suggests that welfare offices may wish to place greater weight on outreach programs that inform more teenagers of the existence of strong child support enforcement measures. Such programs might reduce nonmarital teen motherhood further and thus reduce the need for welfare support and child support enforcement in the long run.

Averaging Lorenz curves

A large number of functional forms has been suggested in the literature for estimating Lorenz curves that describe the relationship between income and population shares. The traditional way of overcoming functional-form uncertainty when estimating a Lorenz curve is to choose the function that best fits the data in some sense. In this paper we describe an alternative approach for accommodating functional-form uncertainty, namely, how to use Bayesian model averaging to average the alternative functional forms. In this averaging process, the different Lorenz curves are weighted by their posterior probabilities of being correct. Unlike a strategy of picking the best-fitting function, Bayesian model averaging gives posterior standard deviations that reflect the functional-form uncertainty. Building on our earlier work (Chotikapanich and Griffiths, 2002), we construct likelihood functions using the Dirichlet distribution and estimate a number of Lorenz functions for Australian income units. Prior information is formulated in terms of the Gini coefficient and the income shares of the poorest 10% and poorest 90% of the population. Posterior density functions for these quantities are derived for each Lorenz function and are averaged over all the Lorenz functions.     

Can formula apportionment really prevent multinational enterprises from profit shifting? The role of asset valuation,intragroup debt,and leases

The European Commission has been supporting a transition from a system of separate accounting to formula apportionment. After its 2011 draft directive was rejected by the Council, the Commission presented two new draft directives in October 2016, one stipulating rules for a common tax base and another the terms for consolidation and apportionment. The aspired system of unitary taxation is considered more resistant to profit shifting and assumed to reduce compliance costs. However, there are also doubts about the extent, to which such a system will eradicate tax-planning activities of MNEs. Other concerns have arisen about the practical issue of enforcing uniform rules for asset valuation throughout the member states. We use a dynamic model of tax accounting based on neoclassical investment theory and effective tax rates to determine to what extent formula apportionment mitigates the efficiency of typical profit-shifting strategies. We focus on the roles of transfer pricing and intragroup debt financing (through loans and leases) under both separate accounting and formula apportionment. We also take into account a possible leeway for inconsistent valuation. Our results show that instead of eliminating tax planning strategies, the proposed system might simply induce a shift from manipulating reported profits to influencing the apportionment key. Inside the European Union, the CCCTB may be able to render thin capitalisation rules and transfer pricing documentation redundant. However, formula apportionment invites for new forms of tax planning. It is therefore essential to give credit to these new kinds of tax incentives when implementing a system of unitary taxation.     

CCR or BCC: what if we are in the wrong model?

The CCR model by Charnes et al. (Eur J Oper Res 2:429–444, 1978) together with the BCC model by Banker et al. (Manag Sci 30:1078–1091, 1984) are the most popular approaches of measuring efficiency among a group of decision making units, DMUs, in data envelopment analysis, DEA. The right choice of a DEA model—CCR or BCC—often, if not always, is a difficult decision. To evaluate a DMU’s efficiency for both models might be helpful, but it does not always capture the essential issues at stake. In this paper we propose a comparative analysis of both concepts: How does activity scaling under constant BCC-efficiency influence CCR-efficiency. And inversely, how does BCC-efficiency behave when activity scaling under constant CCR-efficiency is applied. Such findings of mutual effects improve a DMU’s ability to reassess upsizing and downsizing of activities. Moreover, it allows for exact calculations of the resulting economic effects, and these effects give new insights beyond classical DEA. Finally, scale efficiency turns out to be the ideal concept to control these activity changes, rather than just CCR- or BCC-efficiency. We use a little numerical example to emphasize advantages of the new concept and sketch the new findings for a theater scenery.     

Uniqueness of equilibria in atomic splittable polymatroid congestion games

We study uniqueness of Nash equilibria in atomic splittable congestion games and derive a uniqueness result based on polymatroid theory: when the strategy space of every player is a bidirectional flow polymatroid, then equilibria are unique. Bidirectional flow polymatroids are introduced as a subclass of polymatroids possessing certain exchange properties. We show that important cases such as base orderable matroids can be recovered as a special case of bidirectional flow polymatroids. On the other hand we show that matroidal set systems are in some sense necessary to guarantee uniqueness of equilibria: for every atomic splittable congestion game with at least three players and non-matroidal set systems per player, there is an isomorphic game having multiple equilibria. Our results leave a gap between base orderable matroids and general matroids for which we do not know whether equilibria are unique.     

Optimization problems with color-induced budget constraints

In 1984, Gabow and Tarjan provided a very elegant and fast algorithm for the following problem: given a matroid defined on a red and blue colored ground set, determine a basis of minimum cost among those with k red elements, or decide that no such basis exists. In this paper, we investigate extensions of this problem from ordinary matroids to the more general notion of poset matroids which take precedence constraints on the ground set into account. We show that the problem on general poset matroids becomes -hard, already if the underlying partially ordered set (poset) consists of binary trees of height two. On the positive side, we present two algorithms: a pseudopolynomial one for integer polymatroids, i.e., the case where the poset consists of disjoint chains, and a polynomial algorithm for the problem to determine a minimum cost ideal of size l with k red elements, i.e., the uniform rank-l poset matroid, on series-parallel posets.     

Approximation strategy-proof mechanisms for obnoxious facility location on a line

In the facility location game on a line, there are some agents who have fixed locations on the line where an obnoxious facility will be placed. The objective is to maximize the social welfare, e.g., the sum of distances from the facility to all agents. On collecting location information, agents may misreport the locations so as to stay far away from the obnoxious facility. In this paper, strategy-proof mechanisms are designed and the approximation ratio is used to measure the performances of the strategy-proof mechanisms. Two objective functions, maximizing the sum of squares of distances (maxSOS) and maximizing the sum of distances (maxSum), have been considered. For maxSOS, a randomized 5/3-approximated strategy-proof mechanism is proposed, and the lower bound of the approximation ratio is proved to be at least 1.042. For maxSum, the lower bound of the approximation ratio of the randomized strategy-proof mechanism is proved to be 1.077. Moreover, a general model is considered that each agent may have multiple locations on the line. For the objective functions maxSum and maxSOS, both deterministic and randomized strategy-proof mechanisms are investigated, and the deterministic mechanisms are shown to be best possible.