Co-integration and error-correction modelling of agricultural export supply in Cameroon

Abstract

Estimates of factors influencing Cameroon's exports of cocoa, coffee and cotton are derived in a system of equations using the Engle-Granger and Johansen co-integration and error-correction representation procedures. Two co-integrating vectors involving cocoa and coffee exports as endogenous variables are identified in the system while tests for exogeneity of cotton exports are consistent with the independence of cotton from the other two commodities. These findings are corroborated by estimates of a restricted error-correction model which lead to acceptance of the hypothesis that cocoa and coffee exports are indeed determined endogenously to the system and not linked to cotton exports. Statistical significance of the error-correction terms for cocoa and coffee validates the existence of an equilibrium relationship among the variables in each of these cointegrating vectors. The combined short-run dynamic effect of lagged quantities of cocoa and coffee, ezport/dornestic price ratio and GDP jointly explain changes in exports of cocoa whereas lagged quantities exported do not seem to have a significant short-run dynamic effect on changes in coffee exports. q)

The Spanish Tomato Export Sector of the Almeria Region: An Econometric Approach

“…Previous research of agrarian export functions by Chebil and Briz (2000) used repressors of Spanish vegetable exports, measures of competitiveness, like the Spanish price in comparison with the EU price, income, and a variable of domestic demand (production+exports−imports). Tambi (1999) used one variable of total production in his export function of cocoa and coffee and two variables of domestic and export prices. In researching almonds, Murúa and Araiztegui (1994) preferred to use the variation in production as an exogenous variable jointly with domestic and international prices.…”

Understanding the linkage of urban and rural markets of cassava products in Nigeria

“…Stationary series have a finite variance, transitory innovations from the mean, and tendency for the series to return to their mean value. This mean that a stationary series Yt for example, has a mean, variance and autocorrelation that is constant over time, implying that the error structure is time invariant (Adam, 1992;Tambi, 1999;Niemi, 2003). To carry out the unit root test for stationarity, the Dickey-Fuller (DF) and Augmented Dickey-Fuller (ADF) tests are used to examine each of the variables for the presence of a unit root (an indication of non-stationary).…”

Preferential Price and Trade Tied Aid in Fiji: Implications on Price Stability, Certainty and Output Supply

“…Within this framework, the error correction models (ECM) can provide both the long run and short run elasticities. There are a number of studies that have used ECMs (see Hallam and Zanoli, 1993;Abdulai and Rieder, 1995;Townsend, 1996 andTambi, 1999). Another problem with some of these studies is that they tend to provide supply elasticities for changes in physical inputs ignoring the role of prices on the production and input allocation decisions of farmers.…”