Irish pig supplies--an econometric method of prediction

• Published in: Irish journal of agricultural economics and rural sociology 1982, Vol.9 (1), p.17-29
• Main Author: Cowan, C.A
• Format: Article
• Language: English
• Subjects: Agriculture; Economic forecasting models; Economic models; Forecasting models; Modeling; Polynomials; prices; Statistical forecasts; Supply; Swine; Time series forecasting
• ISSN: 0021-1249

The objective of this study is to establish the relationship between prices received by producers and pig supplies so that accurate predictions may be made of future supplies. Geometric lag and polynomial lag distributed models were tested. Other variables besides producer pig prices such as feed prices and seasonal variables were included in the analysis. The models' predictive abilities were tested over four quarters using two forecast measures, mean absolute error and Thiel's U statistic. The geometric lag model with a pig price/feed price ratio as a variable gave consistently good results for both measures of evaluation. The same model with separate pig price and feed price variables and the polynomial models gave good results with the mean absolute error measure but less satisfactory U-values. From mid-1980 onwards the large volume of imports from Northern Ireland made prediction with the models unsatisfactory. The price ratio geometric lag model has potential for forecasting purposes, but it is necessary to establish the levels of genuine trade before usage for regular predictions can be recommended.