GenERRate: generating errors for use in grammatical error detection

This paper explores the issue of automatically generated ungrammatical data and its use in error detection, with a focus on the task of classifying a sentence as grammatical or ungrammatical. We present an error generation tool called GenERRate and show how GenERRate can be used to improve the performance of a classifier on learner data. We describe initial attempts to replicate Cambridge Learner Corpus errors using GenERRate

Social Mobility in Bolivia is Finally Improving!

This paper evaluates the degree of social mobility in Bolivia, both by comparing to other Latin American countries, and by comparing social mobility at different points in time. While Bolivia had one of the lowest levels of social mobility in the region in 1997, the last 10 years have seen spectacular improvements, especially for rural and female teenagers. This is very good news, as it suggests that Bolivia has finally escaped the low mobility – low growth equilibrium where it has been stuck for so long.Social Mobility, Bolivia

Convergence Analysis of an Inexact Feasible Interior Point Method for Convex Quadratic Programming

In this paper we will discuss two variants of an inexact feasible interior point algorithm for convex quadratic programming. We will consider two different neighbourhoods: a (small) one induced by the use of the Euclidean norm which yields a short-step algorithm and a symmetric one induced by the use of the infinity norm which yields a (practical) long-step algorithm. Both algorithms allow for the Newton equation system to be solved inexactly. For both algorithms we will provide conditions for the level of error acceptable in the Newton equation and establish the worst-case complexity results

Time-Dependent Random Walks and the Theory of Complex Adaptive Systems

Motivated by novel results in the theory of complex adaptive systems, we analyze the dynamics of random walks in which the jumping probabilities are {\it time-dependent}. We determine the survival probability in the presence of an absorbing boundary. For an unbiased walk the survival probability is maximized in the case of large temporal oscillations in the jumping probabilities. On the other hand, a random walker who is drifted towards the absorbing boundary performs best with a constant jumping probability. We use the results to reveal the underlying dynamics responsible for the phenomenon of self-segregation and clustering observed in the evolutionary minority game.Comment: 5 pages, 2 figure

Informality and Productivity in Bolivia: A Gender Differentiated Empirical Analysis

The urban labor market in Bolivia can be divided into 4 main sectors: 1) the public sector, 2) the formal private sector, 3) self-employed informals, and 4) informal workers. Although incomes are generally higher in the public sector and in the formal private sector, there is a strong preference in Bolivia for being informally self-employed. Two thirds of both men and women in urban areas respond that they would prefer to be self-employed rather than a salaried employee, and few see any advantage of becoming formal under the current institutional set-up. Currently, half of all economically active women in urban areas are informally self-employed, while this is the case for only one third of men. This implies that women are actually closer to the desired state than men, according to their own preferences. The real problem for women is not that they are informally self-employed, but rather that the profitability of their informal enterprises is low. On average, monthly profits of female micro-entrepreneurs is about 40% lower than those of male micro-entrepreneurs. This report uses quantitative information from about 600 micro and small enterprises to break down and understand this gender gap in profitability, and the results show that almost the whole gap is due to the fact that women operate their businesses on a much smaller scale (with less productive capital and fewer employees) than men. Why do female entrepreneurs operate on a smaller scale? One partial explanation is that they do not want to grow, because the business then would loose some of the features that make a micro-business particularly attractive for women (not to depend on others, to be able to care for children simultaneously, flexible working hours, and daily revenues). More important, however, is the lack of access to capital. Micro and small businesses operated by women have only a third of the operating capital of male operated businesses. There are two main reasons for this. First, women generally have fewer opportunities to accumulate capital, both because their household and reproductive work takes time away from paid work, and because they tend to earn less than men when they do work for money. Second, they do not have access to credit on reasonable terms. Access by itself is not the problem, as there is a very active micro-credit industry in Bolivia, but the terms are so unattractive that women try to avoid it if at all possible. The interest rates are high (20-40% per year); the group-lending practices increases the risk for the borrower, as they may end up paying other group members’ debt also; and they are typically required to assist at compulsory training courses twice a month, which is demanding for busy women running both a business and a household. Banks offer loans at more reasonable terms, but the requirements are difficult for micro-entrepreneurs to comply with (especially proof of a monthly pay check) and the risk is large as an entire house is often put up as collateral for even a small loan. Capital and credit is not a binding constraint in all sectors, however. On average, returns to additional capital investments are estimated to be relatively high (internal rates of return of over 20%) in the food sales sector, the textile clothing sector, and the camelid clothing sector. In contrast, they are estimated to be negative for grocery stores and the transport sector, which have experienced overinvestment to the extent that the returns to both capital and labor in these two sectors have been severely depressed. Even in the sectors where returns to capital are relatively high, a doubling of productive capital would not lead to a doubling of monthly profits. In fact, estimation results show strongly diminishing returns to scale, which means that micro-enterprises have little incentive to grow. Under the current institutional setup in Bolivia, it makes more economic sense to have several identical micro-enterprises in the family rather than one larger enterprise, and this is indeed often observed in practice. This is partly due to the characteristics of the sectors (for example, several small stores can capture a larger market due to the geographical dispersion), but it is mostly due to the tax-system, which becomes very demanding, both in terms of bureaucratic procedures and in terms of tax burden, as soon as an enterprise grows past a certain threshold. Under the current institutional set up, micro-entrepreneurs perceive no benefits from becoming formal, and indeed estimation results confirm that formality would lower the monthly profits of micro-enterprises (less than 3 workers and less than $1000 in operating capital) by 30-40%. Slightly bigger firms (3-5 workers), however, may benefit from getting a NIT and thus be able to offer facturas to the clients.Informality, Productivity, Gender, Bolivia

Social Impacts of Climate Change in Mexico: A municipality level analysis of the effects of recent and future climate change on human development and inequality

This paper uses municipality level data to estimate the general relationships between climate, income and child mortality in Mexico. Climate was found to play only a very minor role in explaining the large differences in income levels and child mortality rates observed in Mexico. This implies that Mexico is considerably less vulnerable to expected future climate change than other countries in Latin America.Climate change, social impacts, Mexico

Regional Integration and Poverty: A case study of Bolivia

This paper investigates the impacts of regional integration processes on poverty in Bolivia. It first demonstrates that regional integration has stimulated a diversion of trade away from traditional US and EU markets towards countries of MERCOSUR and the Andean Community. At the same time, the composition of exports has changed from predominantly minerals towards slightly more elaborated goods, such as vegetable fats, food and beverages. The paper presents econometric analyses of the impact of imports, exports and FDI (by sector, and trade block) on individual labor incomes and household poverty status. The results show that higher exports generally tend to benefit the workers who work in the exporting sectors. However, this result only holds for export sectors that exploit some natural resource rents (mining, hydrocarbons, modern agriculture), and not for those which rely purely on low wages in order to be competitive (most manufacturing sectors). Imports typically have a negative effect on worker salaries, except the imports of capital goods, which do not compete with local production. This implies that the change towards more regional trade of goods with a smaller natural resource rent component is unlikely to contribute to a reduction in poverty. For exports and FDI to be helpful for reducing poverty, they would have to focus on sectors, which are labor intensive and at the same time exploit some natural resource rents. Sectors that might fulfill these criteria are modern agriculture and tourism.Regional integration, poverty, Bolivia

Labor Mobility in Bolivia: On-the-job Search Behavior of Private and Public Sector Employees

This paper estimates structural parameters of both a simple and an extended job separation model with the purpose of understanding constraints in the labor market in Bolivia. The results confirm the hypothesis that skilled labor is a scarce commodity in Bolivia, while unskilled labor is abundantly available. This implies that skilled employees shop around for alternative employment opportunities and quit their jobs when a better opportunity arises. The quit rate among skilled employees in the private sector is much higher than the quit rate among skilled employees in the public sector. The reverse is true for the lay-off rate, and together this suggests that the private sector has difficulties maintaining its skilled labor. The estimates of the wage sensitivity of job search effort parameters presented in this paper suggest that it would be difficult for the private sector to improve its capacity to retain skilled employees by increasing wages – skilled employees in the private sector do not seem to reduce their on-the-job search in response to higher wages. The results are consistent with the hypothesis that the public sector in Bolivia, inflated by high levels of foreign aid (about 10% of GDP), may be detracting scarce human resources from local productive sectors, potentially jeopardizing the opportunity for sustainable development.Mobility, on-the-job search, labor markets, Bolivia