We investigate conditions sufficient for identification of average treatment effects using instrumental variables. First we show that the existence of valid instruments is not sufficient to identify any meaningful average treatment effect. We then establish that the combination of an instrument and a condition on the relation between the instrument and the participation status is sufficient for identification of a local average treatment effect for those who can be induced to change their participation status by changing the value of the instrument. Finally we derive the probability limit of the standard IV estimator under these conditions. It is seen to be a weighted average of local average treatment effects.

Evolution and Rationality Some Recent Game-Theoretic Results. Identification and Estimation of Local Average Treatment Effects

Poverty and Famines: An Essay on Entitlement and Deprivation

This paper uses survey data from 13 countries to document the economic lives of the poor (those living on less than $2 dollar per day per capita at purchasing power parity) or the extremely poor (those living on less than $1 dollar per day). We describe their patterns of consumption and income generation as well as their access to markets and publicly provided infrastructure. The paper concludes with a discussion of some apparent anomalous choices.

The Economic Lives of the Poor

In the epidemiological literature, the fetal origins hypothesis associated with David J. Barker posits that chronic, degenerative conditions of adult health, including heart disease and type 2 diabetes, may be triggered by circumstance decades earlier, in utero nutrition in particular. Economists have expanded on this hypothesis, investigating a broader range of fetal shocks and circumstances and have found a wealth of later-life impacts on outcomes including test scores, educational attainment, and income, along with health. In the process, they have provided some of the most credible observational evidence in support of the hypothesis. The magnitude of the impacts is generally large. Thus, the fetal origins hypothesis has not only survived contact with economics, but has flourished.

/pdf/killing-me-softly-the-fetal-origins-hypothesis-3b7mkniv72.pdf

Killing Me Softly: The Fetal Origins Hypothesis.

In what turned out to be a rhetorical master-move, the 1990 World Development Report from the World Bank defined the “extremely poor” people of the world as those who are currently living on no more than $1 per day per person, measured at the 1985 purchasing power parity (PPP) exchange rate. In 1993, the poverty line was updated to $1.08 per person per day at the 1993 PPP exchange rate, which is the line we use in this paper. Poverty lines have always existed—indeed $1 per day was chosen in part because of its proximity to the poverty lines used by many poor countries.1 However the $1-a-day poverty line has come to dominate the conversations about poverty to a remarkable extent.

/pdf/the-economic-lives-of-the-poor-3yi342uxj3.pdf

The Economic Lives of the Poor.

Fafchamps and Shilpi examine how economic activity and market participation are distributed across space. Applying a nonparametric von Thunen model to Nepalese data, the authors uncover a strong spatial division of labor. Nonfarm employment is concentrated in and around cities, while agricultural wage employment dominates villages located further away. Vegetables are produced near urban centers. Paddy and commercial crops are more important at intermediate distances. Isolated villages revert to self-subsistence. The findings of the study are consistent with the von Thunen model of concentric specialization, corrected to account for city size. Spatial division of labor is closely related to factor endowments and household characteristics, especially at the local level. This paper - a product of Rural Development, Development Research Group - is part of a larger effort in the group to understand the importance of spatical factors in rural development.

https://papers.ssrn.com/sol3/Delivery.cfm/15260.pdf?abstractid=636193&mirid=1

The Spatial Division of Labor in Nepal

The recent literature has shown that subjective welfare depends on relative income. Attempts to test this relationship in poor countries have yielded conflicting results, suggesting that the relationship is not universal or only applies above a certain income level. We revisit the issue using data from Nepal. We find a relative consumption effect that is robust, strong in magnitude, and consistent across consumption expenditure categories. We find no evidence that poor households -- in a relative or absolute sense -- care less about relative consumption than more fortunate ones. Households residing far from markets care more -- not less -- about the consumption level of their neighbors, suggesting that market interaction is not what makes people care about relative consumption. Household heads having migrated out of their birth district still judge the adequacy of their consumption in comparison with households in their district of origin.

Subjective Welfare, Isolation, and Relative Consumption

https://web.stanford.edu/~fafchamp/nepwel.pdf

Internal migration plays an important role in moderating regional differences in well-being. This paper analyzes migrants' choice of destination, using Census and Living Standard Surveys data from Nepal. The paper examines how the choice of a migration destination is influenced by income differentials, distance, population density, social proximity, and amenities. The study finds population density and social proximity to have a strong significant effect: migrants move primarily to high population density areas where many people share their language and ethnic background. Better access to amenities is significant as well. Differentials in expected income and consumption expenditures across districts are found to be relatively less important in determining migration destination choice as their effects are smaller in magnitude than those of other determinants. The results of the study suggest that an improvement in amenities (such as the availability of paved roads) at the origin could slow down out-migration substantially.

Determinants of the Choice of Migration Destination*: Determinants of the choice of migration destination

Using survey data from Nepal, we examine the relationship between proximity to urban centres and the organisation of labour. We show that wards located in and near cities have more diversified and more market oriented activities. This suggests the presence of returns to market specialisation in cities. We also find some evidence of returns to hierarchical specialisation. These effects are felt up to four hours of travel time from large cities. Urbanisation is associated with lower female labour market participation and with a more pronounced specialisation of women either in market-related activities or in strictly home-based chores.

Forhad Shilpi

Papers

The Spatial Division of Labor in Nepal

Subjective Welfare, Isolation, and Relative Consumption

Subjective Welfare, Isolation, and Relative Consumption

Determinants of the Choice of Migration Destination*: Determinants of the choice of migration destination

Cities and Specialisation: Evidence from South Asia