Modelización del comportamiento de los precios spot de varios tipos de café

This paper investigates long-run relationships among the spot prices of four coffee types. We find two cointegrating vectors: one between the prices of Other Milds and Colombian coffee, and the other one between Unwashed Arabicas and Robustas. Following Pesaran and Shin (1996), persistence profile analysis of the two cointegrating vectors shows a rapid adjustment towards their equilibrium value. This suggests that the four coffee markets are highly related, and that discrepancies in the equilibrium relationships are short-lived. Out of sample evaluation of the model is reasonably good, except for two occasions of sharp price increases following adverse weather conditions

A tale of two coffees? Analysing interaction and futures market efficiency

Purpose: The purpose of this paper is to assess the informational efficiency of Arabica (other milds) and Robusta coffee futures markets in terms of predicting future coffee spot prices. Design/methodology/approach: Futures market efficiency is associated with the existence of a long-run equilibrium relationship between spot and future prices such that coffee futures prices are unbiased predictors of future spot prices. This study applies unit root testing to daily data for futures-spot price differentials. A range of maturities for futures contracts are considered, and the study also uses a recursive approach to consider time variation in futures market efficiency. Findings: The other milds and Robusta futures prices tend to be unbiased predictors for their own respective spot prices. The paper further finds that other milds and Robusta futures prices are unbiased predictors of the respective Robusta and other milds spot prices. Recursive estimation suggests that the futures market efficiency associated with these cross cases has increased, though with no clear link to the implementation of the 2007 International Coffee Agreement. Originality/value: The paper draws new insights into futures market efficiency by examining the two key types of coffee and analyses the potential interactions between them. Hitherto, no attention has been paid to futures contracts of the Robusta variety. The employment of unit root testing of spot futures coffee price differentials can be viewed as more stringent than an approach based on non-cointegration testing. © 2020, Emerald Publishing Limited

Response surface models for the Elliott, Rothenberg, and stock unit-root test

In this article, we present response surface coefficients for a large range of quantiles of the Elliott, Rothenberg, and Stock (1996, Econometrica 64: 813- 836) unit-root tests, for different combinations of number of observations, T, and lag order in the test regressions, p, where the latter can either be specified by the user or be endogenously determined. The critical values depend on the method used to select the number of lags. We present the command ersur and illustrate its use with an empirical example that tests the validity of the expectations hypothesis of the term structure of interest rates. © 2017 StataCorp LLC

A note on the extent of U.S. regional income convergence

Long-run income convergence is investigated in the U.S. context. We employ a novel pairwise econometric procedure based on a probabilistic definition of convergence. The time-series properties of all the possible regional income pairs are examined by means of unit root and non-cointegration tests, where inference is based on the fraction of rejections. We distinguish between the cases of strong convergence, where the implied cointegrating vector is [1, -1], and weak convergence, where long-run homogeneity is relaxed. To address cross-sectional dependence, we employ a bootstrap methodology to derive the empirical distribution of the fraction of rejections. We find supporting evidence of U.S. states sharing a common stochastic trend consistent with a definition of convergence based on long-run forecasts of state incomes being proportional rather than equal. We find that the strength of convergence between states decreases with distance and initial income disparity. Using Metropolitan Statistical Area data, evidence for convergence is stronger. © 2013 Cambridge University Press

Coffee export booms and monetary disequilibrium: Some evidence for Colombia

The theoretical models that analyse the monetary consequences of export booms show that under a regime of fixed exchange rates, they affect not only the demand for money, via real income, but also the money supply via foreign exchange accumulation. Within this theoretical framework, this study proposes an empirical approach to determine whether the coffee booms of the second half of the 1970s and mid-1980s led to excess money supply in the Colombian economy. The findings provide evidence in favour of a direct association between coffee export booms and excess money supply, implying that external disturbances jeopardize the ability of the economic authorities to carry out successful monetary policy

Coffee, economic fluctuations and stabilisation: An intertemporal disequilibrium model with capital market imperfections

This paper develops a two-period disequilibrium model of a small open economy under Keynesian unemployment to analyse the effects of temporary, anticipated, and permanent coffee price shocks. The model includes a government sector that administers a commodity price stabilisation fund, and allows for capital market imperfections. The type of capital market imperfection makes an important difference to the results of the model. In particular, when the government borrows on more favourable terms than individuals, the coffee price stabilisation fund reduces the multiplier effects of temporary and permanent shocks not only in the first, but also in the second period. By contrast, when individuals face an upward-sloping supply of capital curve, the stabilisation fund shifts some of these effects from the first to the second period. (C) 2000 Elsevier Science B.V. All rights reserved

On financial liberalization and long-run risk sharing

We address the noted puzzle that despite increased capital mobility, international consumption risk sharing appears to be very limited. For all possible country pairings, we measure idiosyncratic consumption as the difference between national real per capita consumption expenditures. Using a pair-wise framework based on the time-series properties of idiosyncratic consumption, a probabilistic test for non-stationarity suggests that the extent of risk sharing in fact occurs for a large sample of industrial countries. Further to this, we conduct a probit analysis to confirm a statistically significant positive association between the probability of cointegration between national measures of real per capita consumption and the degree of capital mobility. © 2016 CEPII (Centre d'Etudes Prospectives et d'Informations Internationales), a center for research and expertise on the world econom

Response surface models for the Leybourne unit root tests and lag order dependence

This paper calculates response surface models for a large range of quantiles of the Leybourne (Oxf Bull Econ Stat 57:559-571, 1995) test for the null hypothesis of a unit root against the alternative of (trend) stationarity. The response surface models allow the estimation of critical values for different combinations of number of observations, T, and lag order in the test regressions, p, where the latter can be either specified by the user or optimally selected using a data-dependent procedure. The results indicate that the critical values depend on the method used to select the number of lags. An Excel spreadsheet is available to calculate the p-value associated with a test statistic. © 2011 Springer-Verlag

Re-examining the movements of crude oil spot and futures prices over time

We carry out a (partial) replication exercise of Chang and Lee (2015) unit root and cointegration analyses of crude oil spot and futures prices. In doing so, we offer an updated and expanded analysis based on a much wider set of oil futures series than that considered by Chang and Lee, and we consider the impact of different temporal aggregation methods. Although we are not able to exactly replicate their findings, we nonetheless reach qualitatively similar findings to theirs when using their dataset in terms of the long-run properties and interactions of the spot and futures prices data. Likewise, qualitatively comparable results are obtained when using our expanded dataset. However, a number of important qualitative differences from Chang and Lee arise in terms of the analysis of causality between spot and futures contract prices. As part of our replication exercise we also investigate some aspects that were not originally considered by Chang and Lee. In doing this, we find that both the variability of futures prices as well as the speed of adjustment of futures/spot price differentials increase as the maturity of the contracts increase. © 2017 Elsevier B.V

On the dynamics of unemployment in a developing economy: Colombia

This paper estimates an asymmetric error correction model to analyse the dynamic behaviour of the Colombian unemployment rate. It is found that wages above their long-run equilibrium level do increase unemployment, but wages below this level do not reduce it. This finding provides evidence of the existence of hysteresis in the Colombian unemployment rate