Rachid Laajaj

Los Andes University (Colombia) | UNIANDES · Faculty of Economics

Objectives To estimate the risk factors for SARS-CoV-2 transmission in close contacts of adults at high risk of infection due to occupation, participants of the CoVIDA study, in Bogotá D.C., Colombia. Setting The CoVIDA study was the largest COVID-19 intensified sentinel epidemiological surveillance study in Colombia thus far, performing over 60 0...

Background The use of respiratory devices can mitigate the spread of diseases such as COVID-19 in community settings. We aimed to determine the effectiveness of closed face shields with surgical face masks to prevent SARS-CoV-2 transmission in working adults during the COVID-19 pandemic in Bogotá, Colombia. Methods An open-label non-inferiority ra...

Across the world, the COVID-19 pandemic has disproportionately affected economically disadvantaged groups. This differential impact has numerous possible explanations, each with significantly different policy implications. We examine, for the first time in a low- or middle-income country, which mechanisms best explain the disproportionate impact of...

Symptoms-based models for predicting SARS-CoV-2 infection may improve clinical decision-making and be an alternative to resource allocation in under-resourced settings. In this study we aimed to test a model based on symptoms to predict a positive test result for SARS-CoV-2 infection during the COVID-19 pandemic using logistic regression and a mach...

Massive molecular testing for COVID-19 has been pointed out as fundamental to moderate the spread of the pandemic. Pooling methods can enhance testing efficiency, but they are viable only at low incidences of the disease. We propose Smart Pooling, a machine learning method that uses clinical and sociodemographic data from patients to increase the e...

Background: Across the world, the COVID-19 pandemic has disproportionately affected economically disadvantaged groups. This differential impact has numerous possible explanations, each with significantly different policy implications. We examine, for the first time in a low- or middle-income country, which mechanisms best explain the disproportiona...

We study the ex ante motivational effect of a nationwide merit and need-based scholarship in Colombia, which granted full scholarships to low-income students at high-quality universities. Specifically, we analyze how the opportunity to receive the scholarship, influenced the performance of low-income students in the national high-school exit and 9t...

Massive molecular testing for COVID-19 has been pointed out as fundamental to moderate the spread of the pandemic. Pooling methods can enhance testing efficiency, but they are viable only at low incidences of the disease. We propose Smart Pooling, a machine learning method that uses clinical and sociodemographic data from patients to increase the e...

Latin America has been severely affected by the COVID-19 pandemic but estimations of rates of infections are very limited and lack the level of detail required to guide policy decisions. We implemented a COVID-19 sentinel surveillance study with 59,770 RT-PCR tests on mostly asymptomatic individuals and combine this data with administrative records...

Background Epidemiologic surveillance of COVID-19 is essential to collect and analyse data to improve public health decision making during the pandemic. There are few initiatives led by public-private alliances in Colombia and Latin America. The CoVIDA project contributed with RT-PCR tests for SARS-CoV-2 in mild or asymptomatic populations in Bogot...

Increased adoption of improved agricultural technologies is considered an essential step to address global poverty and hunger, and agronomic trials suggest intensification in developing countries could result in large yield gains. Yet the promise of new technologies does not always carry over from trials to real-life conditions, and diffusion of ma...

Can personality traits be measured and interpreted reliably across the world? While the use of Big Five personality measures is increasingly common across social sciences, their validity outside of western, educated, industrialized, rich, and democratic (WEIRD) populations is unclear. Adopting a comprehensive psychometric approach to analyze 29 fac...

Can personality traits be measured and interpreted reliably across the world? While the use of Big Five personality measures is increasingly common across social sciences, their validity outside of western, educated, industrialized, rich, and democratic (WEIRD) populations is unclear. Adopting a comprehensive psychometric approach to analyze 29 fac...

This research analyzes the dynamic processes underlying farmers' learning about heterogeneous returns to new inputs. A RCT was designed to provide an exogenous increase in the farmers' information on input quality and suitability through agronomical trials on their own farm. We study the dynamic impacts of farmers' experimentation with multiple pro...

This paper provides a model where a long-term planning horizon improves economic decisions but also increases the salience of anticipated future utility. Hence, a gloomy future induces the agent to shorten her time horizon in order to reduce distress caused by the anticipation of poverty, at the cost of worsening her realized future consumption, re...

Measures of cognitive, noncognitive, and technical skillsare increasingly used in development economics to analyzethe determinants of skill formation, the role of skills ineconomic decisions, or simply because they are potentialconfounders. Yet in most cases, these measures have onlybeen validated in high-income countries. This paper teststhe relia...

This paper sheds light on the relationship between oil rent and the allocation of talent, toward rent-seeking versus more productive activities, conditional on the quality of institutions. Using a sample of 69 developing countries, we demonstrate that oil resources orient university students toward specializations that provide better future access...

The use of improved seeds and fertilizer contributed to large productivity gains in many parts of the developing world over the last 50 years. And yet this green revolution largely bypassed the African continent, which, over the 1960 to 2000 period, registered the lowest yield increases of all world regions (Evenson and Gollin 2003). According to F...

Evidence has shown that the allocation of talented people affects the long-term growth. It has been found that a large population of engineers tends to foster innovation and growth more rapidly than population of lawyers and other activities with access to the public rent. Yet little is known about what determines the allocation of talents. This pa...

This paper analyzes the impact of economic prospects on one’s time preference. Research in psychol- ogy has shown how individuals modify their preferences in order to reduce their cognitive dissonance, which is the uncomfortable tension felt when simultaneously holding conflicting thoughts. It occurs among the poor when simultaneously caring about...

This paper explores the links among natural disasters, climate change and economic development, and attempts to outline a framework for considering these links. The paper summarises the limited knowledge of the long-term economic impact of natural disasters. Drawing links among disasters, resource management, conflicts and other transmission channe...

The authors assess the effect of economic instability on the success of projects funded by the World Bank using the outcome of the projects, which is a notation of their overall success determined by the Bank's Independent Evaluation Group. It has been argued in macroeconomic studies that aid effectiveness is higher in vulnerable countries because...

Macroeconomic studies have argued that the growth effectiveness of aid is higher in vulnerable countries, because aid dampens the negative effects of economic shocks. Here we present results that support this argument, relying on the analysis of the factors that determine the success or failure of the projects funded by the World Bank. In our econo...

How we measure development determines to a large extent how development priorities are formed. The indices by which we measure success in development have fallen behind the discourse and debates on development. This paper intends to contribute to the determination of common development objectives in two ways. First, we suggest a set of 6 axioms acc...