The Impacts of International Migration on Remaining Household Members: Omnibus Results from a Migration Lottery Program

The impacts of international migration on development in the sending countries, and especially the effects on remaining household members, are increasingly studied. However, comparisons of households in developing countries with and without migrants are complicated by a double-selectivity problem: households self-select into migration, and among households involved in migration, some send a subset of members with the rest remaining whilst other households migrate en masse. We address these selectivity issues using the randomization provided by an immigration ballot under the Pacific Access Category (PAC) of New Zealand’s immigration policy. We survey applicants to the 2002-05 PAC ballots in Tonga and compare outcomes for the remaining household members of emigrants with those for members of similar households who were unsuccessful in the ballots. The immigration laws determine which household members can accompany the principal migrant, providing an instrument to address the second selectivity issue. Using this natural experiment we examine the myriad impacts that migration has on remaining household members, focussing on labor supply, income, durable assets, financial service usage, diet and physical and mental health and use multiple hypothesis testing procedures to examine which impacts are robust. We find the overall impact on households left behind to be largely negative. We also find evidence that both sources of selectivity matter, leading studies which fail to adequately address them to misrepresent the impact of migration.Emigration, Natural Experiment, Selectivity, Wellbeing, Remittances

The Impacts of International Migration on Remaining Household Members: Omnibus Results from a Migration Lottery Program

The impacts of international migration on development in the sending countries, and especially the effects on remaining household members, are increasingly studied. However, comparisons of households in developing countries with and without migrants are complicated by a double-selectivity problem: households self-select into migration, and among households involved in migration, some send a subset of members with the rest remaining whilst other households migrate en masse. We address these selectivity issues using the randomization provided by an immigration ballot under the Pacific Access Category (PAC) of New Zealand's immigration policy. We survey applicants to the 2002-05 PAC ballots in Tonga and compare outcomes for the remaining household members of emigrants with those for members of similar households who were unsuccessful in the ballots. The immigration laws determine which household members can accompany the principal migrant, providing an instrument to address the second selectivity issue. Using this natural experiment we examine the myriad impacts that migration has on remaining household members, focussing on labor supply, income, durable assets, financial service usage, diet and physical and mental health and use multiple hypothesis testing procedures to examine which impacts are robust. We find the overall impact on households left behind to be largely negative. We also find evidence that both sources of selectivity matter, leading studies which fail to adequately address them to misrepresent the impact of migration.wellbeing, selectivity, natural experiment, emigration, remittances

Accounting for selectivity and duration-dependent heterogeneity when estimating the impact of emigration on incomes and poverty in sending areas

The impacts of international emigration and remittances on incomes and poverty in sending areas are increasingly studied with household survey data. But comparing households with and without emigrants is complicated by a triple-selectivity problem: first, households self-select into emigration; second, in some emigrant households everyone moves while others leave members behind; and third, some emigrants choose to return to the origin country. Allowing for duration-dependent heterogeneity introduces a fourth form of selectivity -- one must now worry not just about whether households migrate, but also when they do so. This paper clearly sets out these selectivity issues and their implications for existing migration studies, and then addresses them by using survey data designed specifically to take advantage of a randomized lottery that determines which applicants to the over-subscribed Samoan Quota may immigrate to New Zealand. The analysis compares incomes and poverty rates among left behind members in households in Samoa that sent Samoan Quota emigrants with those for members of similar households that were unsuccessful in the lottery. Policy rules control who can accompany the principal migrant, providing an instrument to address the second selectivity problem, while differences among migrants in which year their ballot was selected allow for estimation of duration effects. The authors find that migration reduced poverty among former household members, but they also find suggestive evidence that this effect may be short-lived as both remittances and agricultural income are negatively related to the duration that the migrant has been abroad.Population Policies,Small Area Estimation Poverty Mapping,Anthropology,Housing&Human Habitats,Remittances

The impacts of international migration on remaining household members : omnibus results from a migration lottery program

The impacts of international migration on development in the sending countries, and especially the effects on remaining household members, are increasingly studied. However, comparisons of households in developing countries with and without migrants are complicated by a double-selectivity problem: households self-select into migration, and among households involved in migration, some send a subset of members with the rest remaining while other households migrate en masse. The authors address these selectivity issues using the randomization provided by an immigration ballot under the Pacific Access Category of New Zealand’s immigration policy. They survey applicants to the 2002-05 ballots in Tonga and compare outcomes for the remaining household members of emigrants with those for members of similar households that were unsuccessful in the ballots. The immigration laws determine which household members can accompany the principal migrant, providing an instrument to address the second selectivity issue. Using this natural experiment, the authors examine the myriad impacts that migration has on remaining household members, focussing on labor supply, income, durable assets, financial service usage, diet, and physical and mental health. The analysis uses multiple hypothesis testing procedures to examine which impacts are robust. The findings indicate that the overall impact on households left behind is largely negative. The findings also reveal evidence that both sources of selectivity matter, leading studies that fail to adequately address them to misrepresent the impact of migration.Population Policies,Access to Finance,Health Monitoring&Evaluation,Housing&Human Habitats,Anthropology

A Selectivity based approach to Continuous Pattern Detection in Streaming Graphs

Cyber security is one of the most significant technical challenges in current times. Detecting adversarial activities, prevention of theft of intellectual properties and customer data is a high priority for corporations and government agencies around the world. Cyber defenders need to analyze massive-scale, high-resolution network flows to identify, categorize, and mitigate attacks involving networks spanning institutional and national boundaries. Many of the cyber attacks can be described as subgraph patterns, with prominent examples being insider infiltrations (path queries), denial of service (parallel paths) and malicious spreads (tree queries). This motivates us to explore subgraph matching on streaming graphs in a continuous setting. The novelty of our work lies in using the subgraph distributional statistics collected from the streaming graph to determine the query processing strategy. We introduce a "Lazy Search" algorithm where the search strategy is decided on a vertex-to-vertex basis depending on the likelihood of a match in the vertex neighborhood. We also propose a metric named "Relative Selectivity" that is used to select between different query processing strategies. Our experiments performed on real online news, network traffic stream and a synthetic social network benchmark demonstrate 10-100x speedups over selectivity agnostic approaches.Comment: in 18th International Conference on Extending Database Technology (EDBT) (2015

Estimating the wage penalty for maternal leave

The focus of this paper is the size of the wage penalty due to maternal leave incurred by working mothers in Germany. Existing estimates suggest two-digit penalties of up to 30 percent, with very little rebound over time. We apply recent panel data methods designed to address problems of sample selectivity, unobserved heterogeneity and endogeneity to German Socio-Economic Panel (GSOEP) data. The selectivity issue arises because no wage is observed for employees who are on leave. Heterogeneity takes the form of unobserved individual effects correlated with explanatory variables. Endogeneity is due to the simultaneity of the wage and participation outcomes. Heckman’s classic treatment of selectivity requires extensions to deal with both heterogeneity and simultaneity. We present an extension for the case of a censored tobit participation model and use it to exploit the actual working hours data available in GSOEP. We also investigate the sensitivity of the results to the choice of method. Our estimates imply a wage penalty due to maternal leave which although substantial remains below previous estimates. Furthermore, we find that this penalty is less persistent than other studies suggest. Five years after the career interruption mothers seem to have caught up.education, training and the labour market;

Selectivity in binary fluid mixtures: static and dynamical properties

Selectivity of particles in a region of space can be achieved by applying external potentials to influence the particles in that region. We investigate static and dynamical properties of size selectivity in binary fluid mixtures of two particles sizes. We find that by applying an external potential that is attractive to both kinds of particles, due to crowding effects, this can lead to one species of particles being expelled from that region, whilst the other species is attracted into the region where the potential is applied. This selectivity of one species of particle over the other in a localized region of space depends on the density and composition of the fluid mixture. Applying an external potential that repels both kinds of particles leads to selectivity of the opposite species of particles to the selectivity with attractive potentials. We use equilibrium and dynamical density functional theory to describe and understand the static and dynamical properties of this striking phenomenon. Selectivity by some ion-channels is believed to be due to this effect.Comment: 11 pages, 9 figure

Imprinting Patterns of Neutral Atoms in an Optical Lattice using Magnetic Resonance Techniques

We prepare arbitrary patterns of neutral atoms in a one-dimensional (1D) optical lattice with single-site precision using microwave radiation in a magnetic field gradient. We give a detailed account of the current limitations and propose methods to overcome them. Our results have direct relevance for addressing of planes, strings or single atoms in higher dimensional optical lattices for quantum information processing or quantum simulations with standard methods in current experiments. Furthermore, our findings pave the way for arbitrary single qubit control with single site resolution.Comment: 9 pages, 7 figure