4.16.2015

Social welfare and robots

As long as we're on the joint topics of ways to end an abstract and social welfare:
"Policies that redistribute income across generations can ensure that a rise in robotic productivity benefits all generations."
The ungated NBER working paper is here. (h/t Tyler Cowen, who has some thoughts on the general issue)

4.08.2015

Social welfare

Meanwhile, in excellent ways to end an abstract:
"[The policy] would also generate a significant welfare gain from the ex-ante standpoint of a newborn under the veil of ignorance."
The original paper is here

4.06.2015

Data-driven causal inference

Distinguishing cause from effect using observational data: methods and benchmarks

From the abstract:
The discovery of causal relationships from purely observational data is a fundamental problem in science. The most elementary form of such a causal discovery problem is to decide whether X causes Y or, alternatively, Y causes X, given joint observations of two variables X, Y . This was often considered to be impossible. Nevertheless, several approaches for addressing this bivariate causal discovery problem were proposed recently. In this paper, we present the benchmark data set CauseEffectPairs that consists of 88 different "cause-effect pairs" selected from 31 datasets from various domains. We evaluated the performance of several bivariate causal discovery methods on these real-world benchmark data and on artificially simulated data. Our empirical results provide evidence that additive-noise methods are indeed able to distinguish cause from effect using only purely observational data. In addition, we prove consistency of the additive-noise method proposed by Hoyer et al. (2009).
From the arxiv.org blog (note):
The basis of the new approach is to assume that the relationship between X and Y is not symmetrical. In particular, they say that in any set of measurements there will always be noise from various cause. The key assumption is that the pattern of noise in the cause will be different to the pattern of noise in the effect. That’s because any noise in X can have an influence on Y but not vice versa.
There's been a lot of research in stats on "causal discovery" techniques, and the paper in essence is running a horse race between Additive-Noise Methods and Information Geometric Causal Inference, with ANM winning out. Some nice overview slides providing background are here.

4.02.2015

Disasters and religiosity

Jeanet Sinding Bentzen has a new version of her working paper on disasters (mostly earthquakes) and religiosity:
Acts of God: Religiosity and Natural Disasters Across Subnational World Districts
Religiosity affects everything from fertility and labor force participation to health. But why are some societies more religious than others? To answer this question, I test the religious coping theory, which states that many individuals draw on their religious beliefs to understand and deal with adverse life events. Combining subnational district level data on values across the globe from the World Values Survey with spatial data on natural disasters, I find that individuals are more religious when their district was hit recently by an earthquake. And further, that individuals are more religious when living in areas with higher long term earthquake risk. Using data on children of immigrants in Europe, I document that this is mainly due to a long-term effect: high religiosity levels evolving in high earthquake risk areas, is passed on through generations to individuals no longer living in high earthquake risk areas. The impact is global: earthquakes increase religiosity both within Christianity, Islam, and Hinduism, and within all continents. Last, I document that the results are consistent with the literature on religious coping and inconsistent with alternative theories of insurance or selection.
Selected quote:
"The estimates indicate that increasing earthquake risk by 30 percentiles from the median increases religiosity by 9 percentiles. The tendency is global: Christians, Muslims, and Hindus all exhibit higher religiosity in response to elevated earthquake risk, and so do inhabitants of every continent."
 via Amir.