Flows of people,flows of ideas,and the inequality of nations

The present paper examines a neglected determinant of aggregate productivity: temporary cross-border flows of people. We hypothesize that interaction between people from different nations facilitates the international diffusion of ideas, thus stimulating aggregate productivity. In order to assess the causal impact of people flows on productivity, we construct an instrument for people flows. By analogy to the trade/growth literature, this instrument is derived from a fitted gravity equation involving geographic determinants of bilateral travel flows. Our cross-section analysis reveal that greater international interaction leads to higher productivity; a very similar result, qualitatively as well as quantitatively, is obtained when we employ dynamic panel data methods for the purpose of identification.     

Means-end chain analysis explains soil fertility management decisions by peri-urban vegetable growers in Kenya

Past studies of the use of soil fertility management strategies by farmers usually model input use decisions based on the neoclassical utility/profit maximization principle in which farmers use soil fertility management inputs primarily to increase revenues and profits. However, there is, to date, no study that explains exactly how this decision-making process occurs and the role which personal values play in driving the choice of soil fertility management inputs. This article systematically maps the relationship between choice of soil fertility management strategy (attributes), its outcomes (consequences) and the personal values that motivate the choice. It specifically uses the means-end chain approach to construct hierarchical value maps that relate the attributes to consequences, and ultimately to the personal values. The study finds that the use of soil fertility management strategies by peri-urban fresh vegetable growers is driven by five personal values, namely happiness, comfortable life, independence, good/healthy life and achievement of life goals. It also finds that while farmers seek to increase profit (hence incomes), profit maximization is not the end driver of the use of soil fertility management inputs. It concludes that a lot more goes into farmers’ decision-making process relating to the use of soil fertility management practices than can be explained by the neoclassical profit/utility maximization principle. The study discusses the policy implications of these findings.     

Energy distribution and economic growth

This research examines the physical constraints on the growth process. In order to run, maintain and build capital energy is required to be distributed to geographically dispersed sites where investments are deemed profitable. We capture this aspect of physical reality by a network theory of electricity distribution. The model leads to a supply relation according to which feasible electricity consumption per capita rises with the size of the economy, as measured by capital per capita. Specifically, the relation is a simple power law with an exponent assigned to capital that is bounded between 1/2 and 3/4, depending on the efficiency of the network. Together with an energy conservation equation, capturing instantaneous aggregate demand for electricity, we are able to provide a metabolic-energetic founded law of motion for capital per capita that is mathematically isomorphic to the one emanating from the Solow growth model. Using data for the 50 US states 1960–2000, we examine the determination of growth in electricity consumption per capita and test the model structurally. The model fits the data well. The exponent in the power law connecting capital and electricity is 2/3.     

Physiological constraints and the transition to growth: implications for comparative development

It is a well known fact that economic development and distance to the equator are positively correlated variables in the world today. It is perhaps less well known that as recently as 1500 C.E. it was the other way around. The present paper provides a theory of why the ‘latitude gradient’ changed sign in the course of the last half millennium. In particular, we develop a dynamic model of economic and physiological development in which households decide upon the number and nutrition of their offspring. In this setting we demonstrate that relatively high metabolic costs of fertility, which may have emerged due to positive selection towards greater cold tolerance in locations away from the equator, would work to stifle economic development during pre-industrial times, yet allow for an early onset of sustained growth. As a result, the theory suggests a reversal of fortune whereby economic activity gradually shifts away from the equator in the process of long-term economic development. Our empirical results give supporting evidence for our hypothesis.

     

Is Declining Productivity Inevitable?

Fertility has been declining on all continents for the last couple of decades and this development is expected to continue in the future. Prevailing innovation-based growth theories imply, as a consequence of scale effects from the size of population, that such demographic changes will lead to a major slowdown in productivity growth. In this paper we challenge this pessimistic view of the future. By allowing for endogenous human capital in a basic R&D driven growth model we develop a theory of scale-invariant endogenous growth according to which population growth is neither necessary nor conductive for economic growth.     

Technological progress and regress in pre-industrial times

This paper offers micro-foundations for the dynamic relationship between technology and population in the pre-industrial world, accounting for both technological progress and the hitherto neglected but common phenomenon of technological regress. A positive feedback between population and the adoption of new techniques that increase the division of labor explains technological progress. A transient shock to productivity or population induces the neglect of some techniques rendered temporarily unprofitable, which are therefore not transmitted to the next generation. Productivity remains constrained by the smaller stock of knowledge and technology has thereby regressed. A slow process of rediscovery is required for the economy to reach its previous level of technological sophistication and population size. The model is employed to analyze specific historical examples of technological regress.

Jared Diamond, Ten Thousand Years of Solitude, 1993.