A hierarchical Bayesian model for forecasting state-level corn yield |
| |
Authors: | Balgobin Nandram Emily Berg Wendy Barboza |
| |
Institution: | 1. Department of Mathematical Science, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA, 01609, USA 2. Department of Statistics, Iowa State University, Snedecor Hall, Ames, IA, 50011, USA 3. National Agricultural Statistics Service, Fairfax, VA, 22030-1504, USA
|
| |
Abstract: | Historically, the National Agricultural Statistics Service crop forecasts and estimates have been determined by a group of commodity experts called the Agricultural Statistics Board (ASB). The corn yield forecasts for the “speculative region,” ten states that account for approximately 85 % of corn production, are based on two sets of monthly surveys, a farmer interview survey and a field measurement survey. The members of the ASB subjectively determine a forecast on the basis of a discussion of the survey data and auxiliary information about weather, average planting dates, and crop maturity. The ASB uses an iterative procedure, where initial state estimates are adjusted so that the weighted sum of the final state estimates is equal to a previously-determined estimate for the speculative region. Deficiencies of the highly subjective ASB process are lack of reproducibility and a measure of uncertainty. This paper describes the use of Bayesian methods to model the ASB process in a way that leads to objective forecasts and estimates of the corn yield. First, we use small area estimation techniques to obtain state-level forecasts. Second, we describe a way to adjust the state forecasts so that the weighted sum of the state forecasts is equal to a previously-determined regional forecast. We use several diagnostic techniques to assess the goodness of fit of various models and their competitors. We use Markov chain Monte Carlo methods to fit the models to both historic and current data from the two monthly surveys. Our results show that our methodology can provide reasonable and objective forecasts of corn yields for states in the speculative region. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|