This study considers the eradication of hookworm disease from the American South (circa 1910) as a test of the quantity-quality (Q-Q) framework of fertility. Eradication was principally a shock to the price of quality because of three factors: hookworm (i) depresses the return to human capital investment, (ii) had a very low case-fatality rate, and (iii) had negligible prevalence among adults. Consistent with the Q-Q model, we find a significant decline in fertility associated with eradication.

Emerging markets firms often carry foreign-currency debt on their balance sheets. Following a depreciation, the expanding “peso” value of “dollar” liabilities could, via a net-worth effect, offset the expansionary competitiveness effect. To assess which effect dominates, we use accounting data (including the currency composition of liabilities) for 450+ nonfinancial firms in five Latin American countries in the 1990s. We find that firms holding more dollar debt do not invest less than their peso-indebted counterparts following a depreciation. We also show that these firms match the currency denomination of their liabilities with the exchange rate sensitivity of their profits.

Research on the effect of language skills on earnings is complicated by the endogeneity of language skills. This study exploits the phenomenon that younger children learn languages more easily than older children to construct an instrumental variable for language proficiency. We find a significant positive effect of English proficiency on wages among adults who immigrated to the United States as children. Much of this effect appears to be mediated through education. Differences between non-English-speaking origin countries and English-speaking ones that might make immigrants from the latter a poor control group for nonlanguage age-at-arrival effects do not appear to drive these findings.