Meta-regression analysis: Producing credible estimates from diverse evidence

Good policy requires reliable scientific knowledge, but there are many obstacles. Most econometric estimates lack adequate statistical power; some estimates cannot be replicated; publication selection bias (the selective reporting of results) is common; and there is wide variation in the evidence base on most policy issues. Meta-regression analysis offers a way to increase statistical power, correct the evidence base for a range of biases, and make sense of the unceasing flow of contradictory econometric estimates. It enables policymakers to develop evidence-based policies even when the initial evidence base lacks credibility

The Allocation of Development Aid Assistance: Do new donors have old motives?

The aid allocation literature explores the motives behind development aid assistance. This literature is enormous, yet surprisingly, the extant empirical studies have in the main only focused on the motives of established donors. Consequently, relatively little is known of the motives of new donors. This paper explores the aid allocation motives of three relatively new DAC donors: Greece, Luxembourg, and Portugal. Both OLS and Tobit two-way effects estimators are used to model their aid allocation process. The results indicate that humanitarian concerns are not an important factor for these three donors. Greece contributes aid predominately to its neighbors and to transitional East European nations. Portugal is motivated by commercial interests and former colony status. The bandwagon effect exists in reverse for Portugal. Commercial interests operate also for Luxembourg. Additionally, Luxembourg appears to donate to smaller more developed countries and is less inclined to donate to East European nations.foreign aid allocation, bilateral aid, economic development, humanitarian concerns.

How Large is Large? Preliminary and relative guidelines for interpreting partial correlations in economics

An essential part of empirical economics research is the identification of the size of an empirical effect. Partial correlations offer a convenient statistically based measure of the strength of an economic relationship. A key question arises in their interpretation: When is a partial correlation large? This paper draws upon the observed distribution of 22,000 partial correlations from a diverse group of economics fields. The median absolute partial correlation from these fields is 0.173, which under Cohen’s (1988) conventional guidelines for zero order correlations is a small to moderate effect. The paper develops new guidelines for key qualitative categories (small, medium and large). According to the new guidelines, partial correlations that are larger than ± 0.33 can be deemed to be large. This is considerably different to Cohen’s guideline of ±0.50 for zero order correlations. Researchers and meta-analysts should exercise caution when applying Cohen’s guidelines to describe the importance of partial correlations in economics.partial correlations; guidelines; empirical economics; meta-analysis

Rankings of Economists in Teaching Economics Departments in Australia, 1988-2000

This paper provides rankings of individual Australian economists in teaching economics departments on the basis of ECONLIT journal articles for the periods 1988-2000 and 1995-2000. In ranking the economists, two types of rankings of journals are employed and approximately 400 journals are taken into account. These are the citation-based rankings and the perception-based rankings.Two different citation-based journal rankings, those by Laband and Piette (1994) and Kalaitzidakis, Mamuneas and Stengos (2001) are used. Perception-based journal rankings from Mason, Steagall and Fabritius are used. The rankings are provided for both 1988-2000 and for 1995-2000.

American trade policy towards Sub Saharan Africa –- a meta analysis of AGOA

Twelve econometric studies investigating the impact of agoa presented in this paper have reported 174 different estimates. In testing for publication bias and whether there is a genuine empirical impact of agoa we resort to a meta-analysis. The meta-analysis provides us with a formal means of testing for publication bias and an empirical effect. The result shows significant publication bias in the selected studies. However, in a few cases the test for a genuine effect is passed successfully. The results of the meta-analysis indicates that agoa increased the trade of beneficiaries by 13.2%

Meta-Regression Methods for Detecting and Estimating Empirical Effects in the Presence of Publication Selection

This study investigates the small-sample performance of meta-regression methods for detecting and estimating genuine empirical effects in research literatures tainted by publication selection. Publication selection exists when editors, reviewers or researchers have a preference for statistically significant results. Meta-regression methods are found to be robust against publication selection. Even if a literature is dominated by large and unknown misspecification biases, precision-effect testing and joint precision-effect/meta-significance testing can provide viable strategies for detecting genuine empirical effects. Publication biases are greatly reduced by combining two biased estimates, the estimated meta-regression coefficient on precision (1/Se) and the unadjusted average effect.Meta-analysis, Publication selection bias, Meta-regression analysis, Precision, Funnel graphs

Efficiency of Root Crop Production in the Fiji Islands

Improvements in the efficiency of agricultural production represent an important source of growth for the Fiji Islands economy. An analysis of the nature and extent of efficiency differences between root crop farmers suggests that there are modest, but economically significant gains that can be made from improving farm level efficiency. On average, around 25% of root crop production is lost due to technical inefficiency. Although our results did not show that larger producers were more efficient than smaller semi-subsistence producers we did find that focus on a smaller range of crops and concentration on farming in terms of work time both tended to improve the efficiency of farmers that produced dalo. The implications of these results for the agricultural R&D system are discussed. The key policy finding is that given the modest gains in production that are feasible from improving technical efficiency, a major growth in root crop production and consumption is likely to be more dependent on the introduction of new technology than the better dissemination of the existing technology.

American trade policy towards Sub Saharan Africa –- a meta analysis of AGOA

Twelve econometric studies investigating the impact of agoa presented in this paper have reported 174 different estimates. In testing for publication bias and whether there is a genuine empirical impact of agoa we resort to a meta-analysis. The meta-analysis provides us with a formal means of testing for publication bias and an empirical effect. The result shows significant publication bias in the selected studies. However, in a few cases the test for a genuine effect is passed successfully. The results of the meta-analysis indicates that agoa increased the trade of beneficiaries by 13.2%.Trade preference regimes; African Growth and Opportunity Act (AGOA); Publication bias; Meta-Regression Analysis; Funnel plot; Study effect

Institutions and Economic Growth: A Systems Approach

In a simultaneous equations with error components framework, we analyze the institutions-growth relationship. We address individual heterogeneity in cross-country production functions, and endogeneize factor inputs in order to disentangle the direct and indirect effects of institutions on growth. We find that the effects of political freedom on total factor productivity and human capital are positive and significant, but they are negative and significant on physical capital and labor force growth. Economic freedom, on the other hand, has positive and significant effects on total factor productivity, physical and human capital, and labor force growth. The total effects of both freedoms on growth are positiveInstitutions, Growth, Simultaneous Equations, Error Components

Re-visiting the Health Care Luxury Good Hypothesis: Aggregation, Precision, and Publication Biases?

While a growing literature examining the relationship between income and health expenditures suggests that health care is a luxury good, this conclusion is contentiously debated due to heterogeneity of the existing results. This paper tests the luxury good hypothesis using meta-regression analysis, taking into consideration publication selection, precision, and aggregation bias. The findings suggest that publication bias exists, a result that is robust irrespectively of the tests employed. Precision and aggregation bias also appear to play a role in the generation of estimates. The corrected income elasticity estimates range from 0.26 to 0.84, although we cannot reject the luxury good hypothesis for some of the performed corrections.aggregate health expenditure, luxury good, regional health expenditure, health care, income elasticity, meta-regression analysis