Āwhina Revolution: A Bayesian Analysis of Undergraduate and Postgraduate Completion Rates from a Program for Māori and Pacific Success in STEM Disciplines (with Ken Richardson, Zaramasina Clark, Michael Gaines, Sonja Miller, Willie Pearson Jr., Liz Richardson) CBE-Life Sciences Education, (17)1, 2018
[Show Abstract]

Māori and Pacific students generally do not attain the same levels of tertiary success as New Zealanders of European descent, particularly in science, technology, engineering, and mathematics (STEM) subjects. Te Rōpū Āwhina (Āwhina), an equity initiative at Victoria University of Wellington in New Zealand between 1999 and 2015, aimed to produce Māori and Pacific professionals in STEM disciplines who contribute to Māori and Pacific community development and leadership. A hierarchical Bayesian approach was used to estimate posterior standardized completion rates for 3-year undergraduate and 2-year postgraduate degrees undertaken by non–Māori-Pacific and Māori-Pacific students. Results were consistent with an Āwhina effect, that is, Āwhina’s positive influence on (combined) Māori and Pacific success.

Welfare Analysis in an Extended Harris-Todaro Model: An Application of the Atkinson Theorem
The B.E. Journal of Theoretical Economics, (17)1, 2017
[Show Abstract] [Working Paper Version]

I analyze the welfare effects of a policy of modern sector enlargement (MSENL), and a policy of increasing the efficiency of on-the-job search from the urban informal sector (IEOS) in a generalized Harris-Todaro model. I show that MSENL causes a Lorenz worsening of the income distribution and IEOS causes a Lorenz improvement. In a rare direct application of the Atkinson theorem, I conclude that MSENL decreases social welfare and IEOS increases social welfare for all anonymous, increasing and Schur-concave social welfare functions.

The Effect of Tax Expenditures on Automatic Stabilizers: Methods and Evidence (with Kyle Rozema)
Journal of Empirical Legal Studies, (14)3, 548–568, 2017

We study the effect of tax expenditures on the stabilizing power of the tax system. We propose a micro-simulation strategy that exploits links that we identify between automatic stabilizers, tax expenditures, and effective marginal tax rates. Using U.S. tax return micro data from 2000 to 2010, we estimate that, on average, the mortgage interest deduction and the charitable contributions deduction decreased the ability of the tax system to absorb fluctuations in aggregate consumption by an average of 7.4 percent and 3.9 percent, respectively.

Work in Progress

The Dynamic Effects of Immigration

I examine the welfare effects of immigration on United States workers. I build a dynamic search and matching model in which immigrants and natives differ according to their outside options, separation rates, wealth holdings and skill composition. Immigration affects native-born welfare by i) altering the skill composition of the labor force, ii) lowering the expected hiring cost of firms, and iii) altering the rate of return on wealth. I demonstrate that the transition period, during which the economy adjusts to immigration, involves both higher returns to wealth and inferior labor market conditions in comparison to the long run steady state. Thus, accounting for transition dynamics shifts the welfare effects of immigration in favor of wealthy households at the expense of workers.

The Reproducibility of Economics Research (with Sylverie Herbert, Flavio Stanchi and Lars Vilhuber)

Published reproductions or replications of economics research are rare. However, recent years have seen increased recognition of the important role of replication in the scientific endeavor. We describe and present the results of a large reproduction exercise in which we assess the reproducibility of research articles published in the American Economic Journal: Applied Economics over the last decade. 69 of 162 eligible replication attempts successfuly replicated the article's analysis 42.6%. A further 68 (42%) were at least partially successful. A total of 98 out of 303 (32.3%) relied on confidential or proprietary data, and were thus not reproducible by this project. We also conduct several bibliometric analyses of reproducible vs. non-reproducible articles.

Code and Data

Rugby Wanderers

Dataset of playing statistics and birthplace information for every person to have played test rugby for the major nations. Python and R code used to webscrape and construct the data is also available. Download everything from the GitHub repository above. An analysis of the data can be found in this blog post. You can find media coverage of the data at Newsroom and Reuters.


The NBER Stata command taxsim9 calculates federal and state income tax liability using 21 input variables. However, these variables do not include taxable income. Kyle Rozema and I therefore wrote Stata and Matlab programs to calculate US federal tax liability and marginal tax rates from nominal taxable income for years 1913 to 2013. Visit the GitHub repository above for installation instructions.


R package co-authored with Yuxin Chen, Alice Chou and Lars Vilhuber that provides an interface for implementing the source C++ programs of the statistical model proposed in Synthesizing Truncated Count Data for Confidentiality by Sam Hawala, Jerry Reiter and Quanli Wang. Sponsored under NSF grant SES-1131897 to Cornell. Visit the GitHub repository above for instructions.

GitHub and Command Line Notes

These notes form part of a workshop for the annual High Performance Computing for Economists camp held at Cornell University. The goal of the camp is to showcase high-performance techniques and tools targetted at 2nd year PhD students in economics and other social sciences. Trimmed down versions are also available: Command Line Slides, Git Slides.

Website Source Code

This website is adapted from the sustain template developed by Fabio Madeira. It is hosted on Github Pages and powered by Jekyll.

Other Writings

Fair Borders? | Migration Policy in the Twenty-First Century

A chapter in an edited collection discussing New Zealand immigration policy. It is published by Bridget Williams Books. An extract from the chapter was published in the National Business Review and I debated some of its contents in an exchange published by Radio New Zealand. You can find other media coverage at, Radio New Zealand and The Spinoff.

Waiho te Waihotanga

An essay on Māori conservatism published in the Going Global edition of the Oranui Māori literary journal. The essay was also published by e-Tangata.

The Piketty Phenomenon | New Zealand Perspectives

A chapter in a collection of responses to Thomas Piketty's Capital from a range of New Zealand economists and commentators. It is published by Bridget Williams Books. An extract from the chapter was published in idealog. You can find other media coverage at Radio New Zealand and the New Zealand Herald.

The Past Matters: Reflections on Tangata Whenua

An essay in the Pantograph Punch reviewing Tangata Whenua: An Illustrated History, one of the first comprehensive histories of Māori. Tangata Whenua was written by Atholl Anderon, Judith Binney and Aroha Harris, and published by Bridget Williams Books.

How bazaar

A review for the New Zealand Listener of Who Gets What - and Why, a book on Market Design by Alvin Roth.

Unconscious Bias and Education: A comparative study of Māori and African American students

A chapter in a report on unconscious bias and racial achievement gaps in New Zealand. My chapter reviews recent economic literature on racial achievement gaps in the United States, and attempts to draw comparisons between African American and Māori educational and economic outcomes. You can find media coverage by Maori Television,, and Radio New Zealand.