Rita Butzer

The Determinants of Agricultural Production: A Cross-Country Analysis

In this analysis of capitals role in agricultural production, a new construction of data on capital allowed the authors to advance the cross-country study of production functions. The model reveals the relative importance of capital, a finding quite robust to modifications of the model and the disaggregation of capital to its two components. The model is also consistent with the view that lack of physical capital serves as a constraint on agricultural growth. The shift to more productive techniques is associated with a decline in labor, reflecting labor-saving technical changes. This is not news, but it is emphasized here because it comes out an integral view of the process which distinguishes between the core technology and the changes that took place over time and between countries. Not only is capital important to agricultural production, and agricultural development dependent on the economic environment, but agriculture is more cost-capital-intensive than nonagriculture. Capital is all the more important as a factor of production in that land (also important) varies little over time. The availability of agricultural capital determines whether the gap between available and applied technologies can be closed. Prices have little direct, immediate impact on agricultural growth, beyond their impact through inputs and choice of technology. The legacy of past policies that distorted the relative returns to economic activity is enshrined in current stocks, which may respond slowly to policy reform. The analysis assumes that the production technology is heterogeneous and the implemented technology is endogenous and determined jointly with the level of unconstrained inputs. Thus, a change in the state variables affects both the technology and the inputs, so the production function is not identified. To overcome that problem, changes in productivity are decomposed to three orthogonal components caused by the fundamentally different processes underlying panel data. The statistical framework explains the unstable results observed in production functions derived from panel data. Statistically, the results depend on how the data are projected. Comparisons between units over time or of deviations from unit-means or time-means all describe different processes. This is based on theory but has an intuitive appeal as well. In this case, the spread in productivity among countries is different from the spread in productivity for a country through time. The factors explaining the spread will differ. The modeling approach should explicitly recognize the fact that panel data measure a combination of economic phenomena.

A New Database on Investment and Capital for Agriculture and Manufacturing

In this paper, the authors document a new database on sectoral investment and capital, providing details about sources of investment data and the method used to convert those data series into capital stock series. They also provide a copy of the computer program used to implement the method. The data set is available for electronic distribution and will soon be posted on the World Wide Web. They broadly define agricultural capital and calculate series for fixed capital as well as capital embodied in livestock and treestock.

Rethinking Within and Between Regressions: The Case of Agricultural Production Functions

The canonical form of regressions estimated with panel data consists of within-unit-time, between-unit and between-time regressions. These components represent different outcomes of the underlying economic processes. This is demonstrated in the paper by presenting results for the cross-country agricultural production function where the choice of inputs is convoluted with the choice of techniques. The results shed new light on resource productivity in agriculture and its relationship with the implemented technology.

Intersectoral Migration in Southeast Asia: Evidence from Indonesia, Thailand, and the Philippines

Using time series data spanning three decades, the authors examine the determinants of sectoral migration in Indonesia, Thailand and the Philippines. They employ a principal components algorithm to address problems associated with trended and inter-correlated explanatory variables. Migration rates in the three countries are low relative to other developing countries with the consequence of persistent inter-sectoral income differentials. Even so, the rate of migration has been responsive to income ratios in each country. The migration rates were also affected by the absorbing capacity of non-agriculture, as indicated by several measures. In contrast to other studies, policy variables consisting of indicators of physical and human capital had little impact on the migration rate separate from that captured by relative incomes.

Measures of Fixed Capital in Agriculture

Capital is a fundamental component of agricultural production, and the accumulation of capital is key to growth in agriculture and the process of development. Unfortunately, cross-country data sets on agricultural fixed capital are rare. Using a common methodology that allows comparisons across countries, as well as over time, this paper introduces a data series on fixed capital in agriculture, based on national accounts data. The fixed capital measure differs remarkably from the Food and Agriculture Organizations data series on tractors, which has been widely utilized as a proxy for agricultural fixed capital. The authors construct comparable measures of capital in livestock and tree stock. They examine the evolution of the capital stocks from 1970 to 2000, paying particular attention to the changing composition of agricultural capital, as well as differences in the accumulation of capital for high-income and middle and lower-income countries. Using the capital measures in agricultural productivity analyses, the data yield estimated input elasticities substantially different from those found previously in the literature. The authors show explicitly that this is due to the improved data set on agricultural capital stocks, as well as the methodology used in the study.