AN APPLICATION AND EXTENSION OF THE MARKOV CHAIN MODEL TO CEREAL PRODUCTION

Given aggregate time-series data, conventional Markov Chain estimation of the stationary transition probabilities is performed for a model of the cereal market in Great Britain. The possibility of non-stationary probabilities is examined in the light of these initial results, and the basic model developed to allow exogenous variables to enter via their influence on these parameters. The evidence from the paper would appear to suggest that, at least in the case considered, time-varying transition probabilities are a most attractive alternative.     

A FORECAST OF MILK SUPPLY IN ENGLAND AND WALES

This paper reports the problems encountered in applying Markov Chain analysis to the Permanent sample of milk producers in England and Wales, and presents predictions obtained for producer numbers and milk output, by regions, for the years 1970/71 and 1975/76. As a consequence of the “pool of entrants” problem, dificulties arise both in estimating the required transition probabilities and in forecasting producer numbers. Solutions to these, and to other problems concerned with obtaining prediction of milk output, from those of producer numbers, are proposed. It is forecast that producer numbers will decline by 18 per cent and 33 per cent by 1970/71 and 1975/76 respectively, with the largest proportional decline occurring among smaller producers. Two forecasts are made of milk supply and these are compared with estimates made by the Milk Morltetiiic Board.     

THE EVOLUTION OF AGRICULTURAL EXTENSION IN ENGLAND AND WALES PRESIDENTIAL ADDRESS

This paper traces the evolution of agricultural extension in England and Wales and reflects on the reasons for the changes which have occurred in its structure, direction and funding. It describes the change from an extension to a consultancy organisation, analyses the effects of such a change, and examines some of the early mistakes in undertaking it. Questions are raised about whether advice paid for by the client improves the focus of extension and enhances the effectiveness of the relationship between adviser and client. It also questions whether Government policies towards agriculture could be equally well carried out by contracting out the work of extension to the private sector.     

FORECASTING MILK OUTPUT IN ENGLAND AND WALES*

This paper evaluates the ablility of an autoregressive integrated moving average (arima) model to forecast monthly milk output before and after the imposition of quotas in April 1984. In the post quota period the standard arima model is modified to a ‘discontinuity’ model allowing the quota to be represented explicitly. It is concluded that for a medium term forecast this is preferable to the standard arima model, whilst for one period ahead forecasts the models are equally good.     

PRODUCTION CHOICE IN THE ENGLAND AND WALES DAIRY SECTOR

This paper seeks to develop the understanding of the ways in which factors other than price influence the production decisions of dairy farmers. A theoretical model based on a profit function is used to emphasise the way in which changes in the farm's technological environment will influence its production choices. The theoretical model is used as the basis of an empirical study of production choice in the England and Wales dairy sector. Elasticities and factor biases are reported.     

HERD SIZE AND UNIT COSTS OF PRODUCTION IN THE ENGLAND AND WALES DAIRY SECTOR

This paper examines the relationship between herd size and unit costs of production in the England and Wales dairy sector. Following the two-stage estimation procedure of Dawson & Hubbard (1987), longrun average cost (LAC) functions are estimated from cross-section data for five separate years between 1976/7 and 1986/7. Results show that the LAC curves are U-shaped but highly skewed, implying that considerable economies of size are present at low output levels but diseconomies at larger levels are much less marked. Over time, technological change in particular has been shifting the LAC curves downward and to the right and away from the sector's long-run equilibrium. The differential shift of cost curves, depending on the size of production, implies that technological change has been biased in favour of larger herds.     

A REVIEW OF THE ESTIMATION OF TRANSITION PROBABILITIES IN MARKOV CHAINS

A chronological review of the development of estimation procedures for unknown constant Markovian transition probabilities is presented with emphasis on applications involving the availability of macrodata, as opposed to microdata. Monte Carlo results comparing various estimation methods are analysed and several suggestions for estimating non-stationary probabilities are made.     

MANAGEMENT AND SIZE ECONOMIES IN THE ENGLAND AND WALES DAIRY SECTOR

Analyses of size economies in the England and Wales dairy sector have generally been made on the basis of comparisons of input-output measures. These measures have been classified according to input use and farm size and have led to conclusions about efficiency and structural change. This paper examines the influence of managerial ability on economies of size using econometrically estimated long-run average cost (LAC) functions from Milk Marketing Board data for 1980/1. The results show that the LAC curve is U-shaped though skewed to exhibit greater economies than diseconomies of size. Better managed farms are shown to produce any given level of output at lower average cost. Moreover, they have larger optimal levels of output.     

THE ANALYSIS OF NET FARM INCOME: AN EXAMINATION OF FARM MANAGEMENT SURVEY DATA

The practical significance of the conventional “net farm income” is elusive. It would be useful to have an accepted method of dividing “management and investment income” into its recognised Components—managerial salary and return on tenant's capital. One is a residual if the other can be calculated, and both alternatives are considered. An empirical formula is suggested for estimating the managerial salary which may be imputed to the farmer, taking account of his total turnover, his labour bill and his net farm income. This formula is then applied to Farm Management Survey data, for individual farms and for groups of average, high and low performance (output per £ input). The method may permit closer analysis of relative profitability.     

土地流转马尔科夫概率矩阵的设定及应用 ———以福建省泰宁县为例

该文基于福建省泰宁县2003～2008年土地变更数据,运用马尔科夫链对该县2020年土地利用结构进行了预测。认为土地转移概率矩阵的时间尺度应该加长,并根据数据特点以6年作为一个土地用途流转时间段,以6年转移概率矩阵的乘积构建预测所用的转移概率矩阵,并对预测结果的合理性进行了分析。另外,论文利用马尔科夫链预测土地利用结构的所得结果对规划中土地利用平衡表的编制提供了一定帮助。     

COLLECTION OF RELIABLE FARM LEVEL DATA IN LDC's

This paper analyses the difficulties involved in timely processing of farm level survey data in LDC's using a main-frame computer. It then discusses the potential role of micro-computers used in the field to speed up and improve the quality of data collection.     

LONG-RUN AVERAGE COST CURVES IN THE ENGLAND AND WALES DAIRY INDUSTRY - REPLY

Burton, Ozanne and Collinson (1993) present an interesting comment on the issue of long-run average cost (LAC) in the dairy industry. Since their results essentially substantiate the conclusions of Hubbard (1993), the following points are offered as further thoughts which may be of relevance in any subsequent analysis and estimation.