Changing patterns of child labor around the world since 1950 : the roles of income growth, parental literacy, and agriculture

Using country-level data, this report lays out the broad stylized facts regarding the relationship between child labor and per capita GDP, adult literacy, and the share of agriculture in the economy. The relationship between child labor force participation and per capita income is convex and stable over time. The implication is that as a country develops, child labor will decrease, but at a decreasing rate. At some point, further reductions in child labor may require more than just increasing per capita income. Child labor also is affected by the perceived return to child time in the labor market relative to child time in school. The strength of demand for child labor is highly correlated with the share of agriculture in the economy. Parental perception of the importance of education is highly correlated with the parents'own education. A 10 percent decrease in agriculture's share of GDP, decreases child labor by about 20 percent. A 10 percent decrease in adult illiteracy also decreases child labor by 20 percent. In Latin America, all three of these factors have contributed to decreases in child labor since 1950. Increases in per capita income have lowered the child labor participation rate by 2.9 percentage points. The reduction in adult illiteracy was responsible for a 4.2 percentage point reduction in child labor participation and reductions in agriculture's share of production, lowered child labor by an additional 1.2 percentage points. It is possible that income redistribution may lead to lower incidence of child labor, even if increases in average income will not. However, child labor is still found even at the upper end of the income distribution in Latin America. Consequently, income transfer programs alone will not eliminate child labor.

How does working as a child affect wage, income, and poverty asan adult?

The authors use a unique data set on adult earnings in Brazil to study how child labor affects adult earnings through its impacts on work experience, years of schooling, and human capital attained per year of schooling. Adding up these positive and negative effects, their empirical findings suggest that adults who entered the labor market before age 13 earn 20 percent less per hour, have 26 percent lower incomes, and are 14 percent more likely to be in the lowest two income quintiles. Overall, child labor raises the probability of being poor later in life by 13 percent to 31percent. These magnitudes are large. On the other hand, while child labor reduces the productivity of schooling, the net effect of an additional year of schooling on adult wages is still positive, even if the child works while in school. Consequently, policies which delay dropping out of school, even as the child works, appear to be effective at mitigating adult poverty. This report is a promising first step toward a better understanding of the theoretically ambiguous impact of early labor market entry on lifetime labor market outcomes and the dynastic poverty traps discussed below.

Lyndon Array Construction during Burrows-Wheeler Inversion

In this paper we present an algorithm to compute the Lyndon array of a string $T$ of length $n$ as a byproduct of the inversion of the Burrows-Wheeler transform of $T$. Our algorithm runs in linear time using only a stack in addition to the data structures used for Burrows-Wheeler inversion. We compare our algorithm with two other linear-time algorithms for Lyndon array construction and show that computing the Burrows-Wheeler transform and then constructing the Lyndon array is competitive compared to the known approaches. We also propose a new balanced parenthesis representation for the Lyndon array that uses $2n+o(n)$ bits of space and supports constant time access. This representation can be built in linear time using $O(n)$ words of space, or in $O(n\log n/\log\log n)$ time using asymptotically the same space as $T$

Ultralight boson cloud depletion in binary systems

Ultralight scalars can extract rotational energy from astrophysical black holes through superradiant instabilities, forming macroscopic boson clouds. This process is most efficient when the Compton wavelength of the boson is comparable to the size of the black hole horizon, i.e. when the "gravitational fine structure constant" $\alpha\equiv G \mu M/\hbar c\sim 1$. If the black hole/cloud system is in a binary, tidal perturbations from the companion can produce resonant transitions between the energy levels of the cloud, depleting it by an amount that depends on the nature of the transition and on the parameters of the binary. Previous cloud depletion estimates considered binaries in circular orbit and made the approximation $\alpha\ll 1$. Here we use black hole perturbation theory to compute instability rates and decay widths for generic values of $\alpha$, and we show that this leads to much larger cloud depletion estimates when $\alpha \gtrsim 0.1$. We also study eccentric binary orbits. We show that in this case resonances can occur at all harmonics of the orbital frequency, significantly extending the range of frequencies where cloud depletion may be observable with gravitational wave interferometers.Comment: 12 pages, 6 figures. v2: references added, matches published versio