Empirical models, rules, and optimization

This paper considers supply decisions by firms in a dynamic setting with adjustment costs and compares the behavior of an optimal control model to that of a rule-based system which relaxes the assumption that agents are explicit optimizers. In our approach, the economic agent uses believably simple rules in coping with complex situations. We estimate rules using an artificially generated sample obtained by running repeated simulations of a dynamic optimal control model of a firm's hiring/firing decisions. We show that (i) agents using heuristics can behave as if they were seeking rationally to maximize their dynamic returns; (ii) the approach requires fewer behavioral assumptions relative to dynamic optimization and the assumptions made are based on economically intuitive theoretical results linking rule adoption to uncertainty; (iii) the approach delineates the domain of applicability of maximization hypotheses and describes the behavior of agents in situations of economic disequilibrium. The approach adopted uses concepts from fuzzy control theory. An agent, instead of optimizing, follows Fuzzy Associative Memory (FAM) rules which, given input and output data, can be estimated and used to approximate any non-linear dynamic process. Empirical results indicate that the fuzzy rule-based system performs extremely well in approximating optimal dynamic behavior in situations with limited noise.Decision-making. ,econometric models ,TMD ,

A note on taxes, prices, wages, and welfare in general equilibirium models:

Changes in real wages are often used to measure welfare changes. There is a problem, however, in interpreting measures of changes in factor returns when analyzing the impact of changes in taxes — such as tariffs and indirect taxes — that operate as wedges in product and factor markets versus direct taxes that do not work through the price system. One must account for both how the tax is collected and where the tax revenue goes. We sort out how a shift in tax structure will affect the real wage in a model which isolates the price, wage, revenue, and welfare effects. We start from a simple general equilibrium model which accounts for all income and expenditure flows in the economy and includes both traded and domestic goods. We analyze the impact of changes in indirect taxes and tariffs on prices and factor income and demonstrate the pitfalls of using real factor returns as a welfare indicator. There is a transfer effect on factor returns arising from any shift between indirect and direct taxes, regardless of any efficiency effects. Next, we add explicit factor markets to the model and describe the implications for income distribution in an extension of the Jones trade model. We find that the transfer effect dampens the magnification effect of a price change on factor returns, but does not reverse the Stolper-Samuelson results.Trade policy., Welfare economics., Equilibrium (Economics).,

Economy-wide effects of El Niño / Southern Oscillation (ENSO) in Mexico and the role of improved forecasting and technological change

Weather fluctuations, such as those caused by the El Niño Southern Oscillation (ENSO), add to the riskiness associated with agricultural production. Improved predictive capacity may help ameliorate negative impacts of climate and weather shocks on agriculture, but it is possible that the benefits of an improved forecast will be distributed unevenly. In particular, poor farmers may not have access to improved forecasts, or they may not have the means to adapt to new weather information. This paper uses a stochastic computable general equilibrium (CGE) model to examine the distributive effects of improved forecasting of ENSO in Mexico. The particular focus is on agriculture, one of the most vulnerable sectors in the face of ENSO, as well as a sector which provides income to many of the country's poorest households. The model is used to investigate the responsiveness of various sectors of the economy under different degrees of improved predictive capacity and improvements in agricultural technology....The results show that while agricultural losses are small as a share of the overall economy, improved forecasting techniques can eliminate these lossesStochastic analysis ,Agriculture Environmental aspects Mexico ,Climatic changes Models ,Agricultural productivity ,Forecasting ,TMD ,

Reconciling household surveys and national accounts data using a cross entropy estimation method:

This paper presents an approach to reconciling household surveys and national accounts data that starts from the assumption that the macro data represent control totals to which the household data must be reconciled. The economic data gathered in the survey are also assumed to be accurate, or have been adjusted to be accurate. Given these assumptions, the problem is how to use the additional information provided by the national accounts data to re-estimate the household weights used in the survey so that the survey results are consistent with the aggregate data. The estimation approach represents an efficient “information processing rule” using an estimation criterion based on an entropy measure of information. The survey household weights are treated as a prior. New weights are estimated that are close to the prior using a cross-entropy metric and that are also consistent with the additional information. This approach is implemented to reconcile LSMS survey data and macro data for Madagascar. The results indicate that the approach is powerful and flexible, supporting the efficient use of information from a variety of sources to reconcile data at different levels of aggregation in a consistent framework.National income Accounting., Household surveys., Madagascar.,

Productivity and externalities : models of export led growth

In developing countries, industrialization for successful export-led growth has been associated with rapid structural change and growth in productivity. Standard neoclassical growth models have difficulty explaining this change in performance. This paper has developed a simple analytical model incorporating export externalities that capture the large increases in the share of trade and total factor productivity that are associated with export-led growth. It also has developed a second model that breaks growth into its various components, which includes the effects of: (a) factor accumulation; (b) moving factors from areas of low productivity to area of high productivity; (c) exporting heavy and light manufactures; and (d) importing capital goods. The paper implements the second model with data from an archetypal semi-industrial country. The model accounts for the higher total factor productivity growth observed in countries pursuing export-led growth strategies. It also captures the pattern of structural change that such countries experience.Banks&Banking Reform,Achieving Shared Growth,Economic Theory&Research,Environmental Economics&Policies,Economic Growth

COPPER CRISIS AND AGRICULTURAL RENAISSANCE IN ZAMBIA: AN ECONOMY-WIDE ANALYSIS

Zambia's strong dependence on copper exports has suppressed other tradables sectors, indicative of a Dutch disease phenomenon. The current copper crisis will have strong economic effects, possibly reversing such Dutch disease effects. We use a computable general equilibrium model built around a 1995 social accounting matrix to simulate the short- and long-run effects of two scenarios that reflect the current crisis, a 20 percent reduction in world copper prices and a complete collapse of copper mining. Compared to the short run, the long run is characterized by more flexibility in production technology and capital allocation. Both scenarios require a significant reduction in the "non-copper" trade deficit, absorption, and household consumption. The strongest effects occur under the short-run mining-collapse scenario where household consumption falls by 13 percent and the real exchange rate depreciates by 42 percent. In the long run, these effects are approximately half as strong. The short- and long-run impacts of a 20 percent fall in world copper prices include a cut in household consumption by 4-5 percent and real depreciation by 7-10 percent. For all scenarios, the welfare losses for rural households are below the national average. Given that per-capita consumption is lower in rural areas, inequality falls. This distributional outcome is driven by the fact that the agro-food-fiber complex, which produces outputs that are relatively tradable, expands relative to the rest of the economy in terms of value-added, employment, and exports, suggesting that the copper crisis may induce an agricultural renaissance.Zambia, copper, structural adjustment, agriculture, general equilibrium, International Development, C68, O55, Q17, Q32,

External shocks and policy alternatives in small open economies: The case of El Salvador

In this paper we used a dynamic, regionalized computable general equilibrium (CGE) model to analyze the effect of various negative balance of payments shocks on output and employment and the effect of different alternative investment strategies on growth. The model shows clearly how sensitive El Salvador is to remittance or terms of trade shocks. Each 10 percent reduction in remittances lowers gross domestic product (GDP) by 0.2 percent and household consumption by 1.4 percent, with the cost rising as the shock intensifies. Any negative balance of payments shock forces a reduction in absorption, production, and employment and a real devaluation. Because El Salvador's economy is dollarized, that real devaluation can only come about through a fall in domestic prices brought about by recession. We show that the impact of the shock on output depends on how flexible wages are—the impact is smaller when real wages are flexible and greatest when they are fixed in dollars. We used the CGE model to analyze alternative investment strategies for increasing the growth rate. The investment share of GDP is low, and the model makes it clear that without some strategy for increasing investment, the economy's overall growth rate is likely to remain low. We hypothesized two alternative growth rates for investment, both associated with an increase in exogenous technical change. Both strategies require a marginal increase in the share of output devoted to investment. We also showed that if El Salvador can increase the investment share from 15.5 percent to just 16 percent over five years by producing a growth rate in investment of 8 percent per year, and if that increase produces a 1 percent increase in the rate of technical change in all sectors, then the growth rate of the economy will practically double, rising from 2.85 percent to 4.95 percent per year. There are equally favorable effects on employment for unskilled labor and on wages for skilled labor.Development strategies, general equilibrium models, Regional development, Computable general equilibrium (CGE) modeling,

Prospects for growth and poverty reduction i n Zambia, 2001-2015

"Zambia is one of the poorest countries in Africa. Despite substantial reform during the 1990s, the economy has remained heavily dependent on urban-based mining. Copper's long-standing dominance led to a strong bias against agriculture, which undermined the sector's growth and export potential. Consequently poverty has remained concentrated within marginalized rural areas. Recent volatility in copper exports and growing foreign debt indicate the need for further economic diversification and pro-poor growth. These needs have been clearly identified in the country's Poverty Reduction Strategy Paper (PRSP), which outlines a series of policy objectives aimed at combating HIV/AIDS, reversing the deterioration of education and rural infrastructure, and accelerating agricultural growth. This paper uses a computable general equilibrium (CGE) model to assess the potential impact on inequality and poverty of the key PRSP policies, as well as the effects of foreign debt forgiveness and changes in the copper sector. The findings suggest that, in the absence of very rapid growth, the pro-poor policies outlined in the PRSP will not enable Zambia to reach its Millennium Development Goal (MDG) of halving poverty by 2015. Achieving this goal will require gross domestic product (GDP) to grow at an annual rate of over ten percent. Reduction in poverty can however be achieved by addressing HIV/AIDS, which currently reduces annual GDP growth by one percent. Furthermore, substantial poverty-reduction can occur through the acceleration of agricultural growth, although limited market opportunities necessitates supporting investment in rural infrastructure. Overall, the potential of the agricultural sector depends on the government's commitment to reforms and the continued removal of the antiagricultural bias created by the dominant copper sector." Authors' AbstractCopper mines and mining ,Computable general equilibrium (CGE) ,HIV/AIDS Economic aspects ,agricultural sector ,

Modeling Korean Unification

For North Korea, product market integration would generate large welfare gains, sufficient to end the famine. Additional gains could be had through military demobilization. For the South, the impact of product market integration would be trivial, but the impact of factor market integration would be considerable, affecting the composition of output, distribution of income, and rate of growth. Given moderately rapid technological convergence, expected levels of cross-border migration, and equalization of rates on return on capital, per capita incomes in the North would remain well below those in the South for an extended period.

Trade liberalisation and regional integration: the search for large numbers

We surveyed the empirical literature using multi-country computable general equilibrium (CGE) models to analyse potential and actual regional trade agreements (RTAs). The studies indicate that these RTAs improve welfare, that trade creation greatly exceeds trade diversion, and that they are consistent with further global liberalisation. The welfare gains are bigger when models incorporate aspects of ‘‘new trade theory’’ such as increasing returns, imperfect competition, and links between trade liberalisation, total factor productivity growth, and capital accumulation. We also conjectured that an RTA expands market size and stability, allowing firms to pursue economies of fine specialisation, generating additional ‘‘Smithian’’ efficiency gains.International Relations/Trade,