Politics and economics

Corrado Giulietti, Jackline Wahba, Yves Zenou, 21 December 2014

Migration is heavily influenced by social networks. Nonetheless, little is known about the underlying mechanisms. This column uses a new dataset from China to disentangle the effects of strong and weak ties on the migration decision. The findings indicate that strong and weak ties act as complements. Having many weak ties with an urban area amplifies the positive impact of having a strong tie in the same area. 

Samya Beidas-Strom, Andrea Pescatori , 20 December 2014

The recent dramatic fall in oil prices has renewed the interest in the importance of shocks in the oil price volatility. This column presents results from new research on the role of shocks and speculation on oil prices. The authors find that when speculation is short in duration, it has the weakest impact on oil prices and demand shocks have the largest. However, when speculation is allowed to have short- and long-term effects, it is the main contributor to the volatility of oil prices.

Nauro F Campos, 20 December 2014

Argentina is the only country in the world that was 'developed’ in 1900 and ‘developing’ in 2000. Various explanations highlight the roles of trade openness, political institutions, financial integration, financial development, and macroeconomic instability. No study has so far attempted a quantitative assessment of the relative importance of each of these competing factors. This column presents new evidence suggesting that financial development and institutional change are two main factors behind the unusual growth trajectory of Argentina over the last century. 

Enrico Minelli, 19 December 2014

Growth and inequality are back at the centre of the economic debate. This column presents a framework for interpreting Thomas Piketty’s data based on Paul Romer’s model of endogenous growth. Two balanced growth regimes are possible in this framework: one (‘merit’) with a low capital–output ratio, a high interest rate, and high growth; and another (‘rent’) with a higher capital–output ratio, a somewhat lower interest rate, and much lower growth. An increase in the returns to physical capital accumulation compared to innovation could explain a shift from ‘merit’ to ‘rent’.

Marcelo Giugale, 18 December 2014

Sub-Saharan Africa has been growing steadily over the past decade. The main question that policymakers should face is how to sustain the region’s progress. This column argues that the positive growth is due both to good policies and higher prices of certain commodities (such as oil, gas, and minerals). To ensure sustainability governments should not rely only on these higher rents but rather implement policies that take advantage of them. 

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