THE ANDEAN PRICE BAND SYSTEM: EFFECTS ON PRICES, PROTECTION AND PRODUCER WELFARE

The Andean Community's Price Band System (APBS), introduced in 1995, had the announced goal of reducing domestic price instability by buffering fluctuations in international prices through use of a variable import tariff. This paper evaluates the effects of the Andean Price Band System on domestic producer price variability, levels of nominal protection and changes in producer welfare. Application is made to four important food products - maize, rice, sugar and milk - in Colombia, Ecuador and Venezuela, from the period 1990 to 1998. The effects of the APBS on producer price variability are analyzed through 1) comparing coefficients of variation of detrended, monthly deseasonalized real prices before and after the harmonization of the APBS in 1995, and 2) variance decomposition of real domestic prices. For Colombia and Ecuador, the APBS is shown to have successfully reduced real price instability below levels of instability which existed prior to its introduction. Real exchange rate instability also decreased sharply in these two countries following introduction of the APBS. In Venezuela, real price instability is shown to have increased following introduction of the APBS, while real exchange rate instability was unchanged. The APBS' effects on producer price protection are examined through estimation of average nominal protection coefficients for the twelve country-commodity combinations identified above before and after the introduction of the APBS. Results show that in all three countries and four virtually all products, the APBS contributed to increased producer protection. Finally, this paper uses a variant of the Newbery-Stiglitz approach to calculate efficiency benefits due to risk reduction among producers and the transfer benefits created by redistributing income among producers, consumers and government. The results show that the risk reduction benefits created by the APBS are small. Similarly, the income transfer effects, though larger, are also low, and both contribute to generally low levels of estimated producer welfare effects. Overall, the paper concludes that the APBS has been of limited usefulness as a policy instrument designed to reduce producer price variability in an economically efficient manner.Andean Community, price band system, agricultural prices, price stabilization, Demand and Price Analysis,

Gaussian Quadratures vs. Monte Carlo Experiments for Systematic Sensitivity Analysis of Computable General Equilibrium Model Results

Citation: Villoria, N. B., & Preckel, P. V. (2017). Gaussian Quadratures vs. Monte Carlo Experiments for Systematic Sensitivity Analysis of Computable General Equilibrium Model Results. Economics Bulletin, 37(1), 480-+. Retrieved from ://WOS:000398860600043Third-order Gaussian quadratures (GQ) approximate the mean and variance of model results allowing for computationally inexpensive sensitivity analysis to uncertainty in exogenous parameters. Unfortunately, commonly used GQ approaches restrict the marginal distributions of both parameters and results sacrificing valuable distributional information. Using higher order quadratures, or incorporating more uncertain exogenous parameters, rapidly increases the sample size, undermining the rationale for using GQ. In contrast, Monte Carlo methods directly approximate the distribution of model outcomes without restrictive distributional assumptions on exogenous parameters. We argue that current computing capabilities allow for wider use of Monte Carlo methods for conducting stochastic simulations

La enseñanza de las Matemáticas a través de los recursos didácticos en la segunda mitad del siglo XX en Colombia: entre el uso racional y experimental. Para que el alumno aprenda y el maestro enseñe.

Este trabajo se centra en exponer y reflexionar alrededor de los discursos a propósito de la enseñanza y el aprendizaje de la matemática, que hicieron énfasis en la inclusión y empleo de materiales y recursos didácticos para transformar las prácticas pedagógicas de esta asignatura en el aula; y a partir de allí, mostrar las relaciones de estos en el contexto educativo colombiano, para el periodo correspondiente a la segunda mitad del siglo XX en Colombia

Rapid aggregation of global gridded crop model outputs to facilitate cross-disciplinary analysis of climate change impacts in agriculture

We discuss an on-line tool that facilitates access to the large collection of climate impacts on crop yields produced by the Agricultural Model Intercomparison and Improvement Project. This collection comprises the output of seven crop models which were run on a global grid using climate data from five different general circulation models under the current set of representative pathways. The output of this modeling endeavor consists of more than 36,000 publicly available global grids at a spatial resolution of one half degree. We offer flexible ways to aggregate these data while reducing the technical barriers implied by learning new download platforms and specialized formats. The tool is accessed trough any standard web browser without any special bandwidth requirement

Criteria for effective zero-deforestation commitments

Zero-deforestation commitments are a type of voluntary sustainability initiative that companies adopt to signal their intention to reduce or eliminate deforestation associated with commodities that they produce, trade, and/or sell. Because each company defines its own zero-deforestation commitment goals and implementation mechanisms, commitment content varies widely. This creates challenges for the assessment of commitment implementation or effectiveness. Here, we develop criteria to assess the potential effectiveness of zero-deforestation commitments at reducing deforestation within a company supply chain, regionally, and globally. We apply these criteria to evaluate 52 zero-deforestation commitments made by companies identified by Forest 500 as having high deforestation risk. While our assessment indicates that existing commitments converge with several criteria for effectiveness, they fall short in a few key ways. First, they cover just a small share of the global market for deforestation-risk commodities, which means that their global impact is likely to be small. Second, biome-wide implementation is only achieved in the Brazilian Amazon. Outside this region, implementation occurs mainly through certification programs, which are not adopted by all producers and lack third-party near-real time deforestation monitoring. Additionally, around half of all commitments include zero-net deforestation targets and future implementation deadlines, both of which are design elements that may reduce effectiveness. Zero-net targets allow promises of future reforestation to compensate for current forest loss, while future implementation deadlines allow for preemptive clearing. To increase the likelihood that commitments will lead to reduced deforestation across all scales, more companies should adopt zero-gross deforestation targets with immediate implementation deadlines and clear sanction-based implementation mechanisms in biomes with high risk of forest to commodity conversion.ISSN:0959-3780ISSN:1872-949

Governing agriculture-forest landscapes to achieve climate change mitigation

This introduction to the special section on Governing Agriculture-Forest Landscapes to Achieve Climate Change Mitigation reviews external interventions to improve forest conditions and reduce deforestation, and by extension, influence carbon storage in agriculture-forest landscapes. The review is based on a careful survey of 123 cases of project-based and policy interventions to influence land use and forest cover outcomes. We propose that outcomes of interventions can be explained in terms of rights, incentives, and technologies related to land use and apply this framework to examine 12 types of interventions in agriculture-forest landscapes. The analysis of the identified 123 cases raises concerns about consistency of data and comparability of cases. Our preliminary evidence suggests limited association between the stated objective of an intervention and its success. This evidence also suggests that smaller scale and effective enforcement may be positively associated with improved forest outcomes. But the effectiveness of interventions across different agriculture-forest landscapes varies and available evidence does not permit easy generalizations. The variable effects of interventions across different agriculture-forest landscapes point to the need to better understand the forms and functions of interventions and to problems associated with assessing their relative efficacy

Consequences of agricultural total factor productivity growth for the sustainability of global farming: accounting for direct and indirect land use effects

Most of the growth in agricultural output in the last thirty years comes from increases in the efficiency with which both land and non-land inputs are used. Recent work calls for a better understanding of whether this efficiency, known as total factor productivity (TFP), contributes to a more sustainable food system. Key to this understanding is the documented phenomenon that, instead of saving lands, the introduction of technologies that improve agricultural productivity encourage cropland expansion. We extend the results of a recently published econometric model of cross-country cropland change and TFP growth to explore the extent to which improvements in technology were associated with lower greenhouse emissions from land conversion to agriculture as well as with lower land conversion pressures in biodiversity-rich biomes. We focus on the decade of 2001–2010, a period in which our sample of 70 countries (≈75% of global croplands) experienced net land contraction. Except in sub-Saharan Africa and South and East Asia, regional TFP growth was associated with regional land expansion, thus confirming the existence of Jevons paradox in most regions of the world. However, such expansion was more than offset by indirect land use effects stemming from increases in productivity somewhere else. These indirect effects are far from trivial. In the absence of TFP growth, our estimates suggest that ≈125 Mha would have been needed to satisfy demand, half of which are in the four most biodiverse biomes of the world; estimated land use emissions from the ensuing changes in land use range from a lower bound of 17 Gt CO2eq to an upper bound of 84 Gt CO2eq, depending on whether the expansion would have occurred on pasturelands or forest, in contrast to the ≈1 to 15 Gt CO2eq imputed to observed cropland expansion. Our projections of the land needed to satisfy projected growth in TFP per capita during 2018–2023 indicate that current rates of TFP growth are insufficient to prevent further land expansion, reversing in most cases the in-sample trends in land contraction observed during 2001–2010