Journals have pushed for transparency of research through data availability policies. Such data policies improve availability of data and code, but what is the impact on reproducibility? We present results from a large reproduction exercise for articles published in the American Economic Journal: Applied Economics, which has had a data availability policy since its inception in 2009. Out of 363 published articles, we assessed 274 articles. All articles provided some materials. We excluded 122 articles that required confidential or proprietary data or that required the replicator to otherwise obtain the data (44.5% of assessed articles). We attempted to reproduce 152 articles and were able to fully reproduce the results of 68 (44.7% of attempted reproductions). A further 66 (43.4% of attempted reproductions) were partially reproduced. Many articles required complex code changes even when at least partially reproduced. We collect bibliometric characteristics of authors, but find no evidence for author characteristics as determinants of reproducibility. There does not appear to be a citation bonus for reproducibility. The data availability policy of this journal was effective to ensure availability of materials, but is insufficient to ensure reproduction without additional work by replicators.

We develop an algorithm to compute exact solutions to the influence maximization problem using concepts from reverse influence sampling (RIS). We implement the algorithm using GPU resources to evaluate the empirical accuracy of theoretically-guaranteed greedy and RIS approximate solutions. We find that the approximations yield solutions that are remarkably close to optimal - usually achieving greater than 99% of the optimal influence spread. These results are consistent across a wide range of network structures.

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.

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.

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.

Improved predictions of the net and optimum AA supply to dairy cattle in ration formulation models like the Cornell Net Carbohydrate and Protein System (CNCPS) would provide an opportunity to balance diets closer to animal requirements and improve nutrient utilization. Predictions of net AA supply in a dynamic version of the CNCPS were refined by modeling endogenous N (EN) transactions along the entire gastrointestinal tract (GIT) including incorporation of EN into microbial N supply. Studies that used isotopic enrichment of total N from N-Leu infusion to mark endogenous components were used to develop the model. Predictions were close to measured data at the duodenum, ileum and in the feces. Incorporation of EN into microbial N and the original source of EN at various points in the GIT and in the feces were also accurately predicted. The optimum AA supply was determined using a dataset of published studies that infused AA post-ruminally. A logistic model was used to estimate AA requirements for the physiological processes quantified by the model. The optimum AA supply to maximize AA use and minimize wastage was determined where the third derivative of the logistic model was 0. The optimum AA supply was described for all essential AA. Requirements for Met (5.7% EAA) and Lys (15.1% EAA) were similar to previous recommendations, indicating the model was within the range of current data. A log-logistic relationship was observed when the efficiency of AA use was regressed against AA supply relative to ME supply but no relationship was found when AA supply was expressed relative to MP. Considering AA supply relative to energy could improve predictions of AA utilization and indicates the relationships are not separate and linear, but integrated, and depend on the profile of nutrients consumed.

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.

A chapter in an edited collection discussing New Zealand immigration policy 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. Other media coverage is at stuff.co.nz, Radio New Zealand and The Spinoff.

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

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 draws comparisons between African American and Māori educational and economic outcomes. Some media coverage is at stuff.co.nz and Radio New Zealand.

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.

A chapter in a collection of responses to Thomas Piketty's Capital published by Bridget Williams Books. An extract from the chapter was published in idealog. Other media coverage is at Radio New Zealand and the New Zealand Herald.