The Research Summaries in the March 2014 Research Bulletin focus on efficiency of health expenditure (Francesco Grigoli and Javier Kapsoli) and employment growth in European Union countries (Bas B. Bakker and Li Zeng). The Q&A article looks at “Seven Questions on Financial Interconnectedness” (Co-Pierre Georg and Camelia Minoiu). The Research Bulletin also includes a listing of IMF Working Papers, Staff Discussion Notes, and Recommended Readings from the IMF Bookstore. Information on the IMF Economic Review—the research journal of the IMF—is also provided.

Articles in the June 2014 issue of the IMF Research Bulletin look at “The Rise and Fall of Current Account Deficits in the Euro Area Periphery and the Baltics” (Joong Shik Kang and Jay C. Shambaugh) and “The Two Sides of the Same Coin?: Rebalancing and Inclusive Growth in China” (Il Houng Lee, Murtaza Syed, and Xin Wang). The Q&A looks at “Seven Questions on the Monetary Transmission Mechanism in Low-Income Countries” (Andrew Berg, Luisa Charry, Rafael A. Portillo, and Jan Vleck). This issue of the Research Bulletin includes updated listings of IMF Working Papers, Staff Discussion Notes, and Recommended Readings from the IMF Bookstore. Readers can also find information on free access to a featured article from “IMF Economic Review.”

The paper uses a combination of micro-level datasets to document the rise of income polarization—what some have referred to as the “hollowing out” of the income distribution—in the United States, since the 1970s. While in the initial decades more middle-income households moved up, rather than down, the income ladder, since the turn of the current century, most of polarization has been towards lower incomes. This result is striking and in contrast with findings of other recent contributions. In addition, the paper finds evidence that, after conditioning on income and household characteristics, the marginal propensity to consume from permanent changes in income has somewhat fallen in recent years. We assess the potential impacts of these trends on private consumption. During 1998-2013, the rise in income polarization and lower marginal propensity to consume have suppressed the level of real consumption at the aggregate level, by about 31⁄2 percent—equivalent to more than one year of consumption.

The IMF Research Bulletin includes listings of recent IMF Working Papers and Staff Discussion Notes. The research summaries in this issue are “Explaining the Recent Slump in Investment” (Mathieu Bussiere, Laurent Ferrara, and Juliana Milovich) and “The Quest for Stability in the Housing Markets” (Hites Ahir). The Q&A column reviews “Seven Questions on Estimating Monetary Transmission Mechanism in Low-Income Countries” (Bin Grace Li, Christopher Adam, and Andrew Berg). Also included in this issue are updates on the IMF’s official journal, the IMF Economic Review, and recommended readings from IMF Publications.

This issue of the IMF Research Bulletin features recommended readings from IMF Publications and an update on recent IMF Working Papers and IMF Staff Discussion Notes. It also includes a special announcement welcoming Linda Tesar (University of Michigan) as the new editor of “IMF Economic Review.” The Q&A section explores “Seven Questions on China-Africa Relations” (Luiz Almeida, Wenjie Chen, and Oral Williams). The Research Summaries surveys “Income Polarization in the United States” (Ali Alichi, Kory Kantenga, and Juan Sole); and “The Future Wealth of Nations: World Trade in Services” (Prakash Loungani, Saurabh Mishra, Chris Papageorgiou, and Ke Wang).

Is there a minimum tax to GDP ratio associated with a significant acceleration in the process of growth and development? We give an empirical answer to this question by investigating the existence of a tipping point in tax-to-GDP levels. We use two separate databases: a novel contemporary database covering 139 countries from 1965 to 2011 and a historical database for 30 advanced economies from 1800 to 1980. We find that the answer to the question is yes. Estimated tipping points are similar at about 123⁄4 percent of GDP. For the contemporary dataset we find that a country just above the threshold will have GDP per capita 7.5 percent larger, after 10 years. The effect is tightly estimated and economically large.

The Fund has recognized in recent years that one cannot separate issues of economic growth and stability on one hand and equality on the other. Indeed, there is a strong case for considering inequality and an inability to sustain economic growth as two sides of the same coin. Central to the Fund’s mandate is providing advice that will enable members’ economies to grow on a sustained basis. But the Fund has rightly been cautious about recommending the use of redistributive policies given that such policies may themselves undercut economic efficiency and the prospects for sustained growth (the so-called “leaky bucket” hypothesis written about by the famous Yale economist Arthur Okun in the 1970s). This SDN follows up the previous SDN on inequality and growth by focusing on the role of redistribution. It finds that, from the perspective of the best available macroeconomic data, there is not a lot of evidence that redistribution has in fact undercut economic growth (except in extreme cases). One should be careful not to assume therefore—as Okun and others have—that there is a big tradeoff between redistribution and growth. The best available macroeconomic data do not support such a conclusion.

Using a newly constructed dataset on trade in services for 192 countries from 1970 to 2014, this paper shows that services currently constitute one-fourth of world trade and an increasingly important component of global production. A detailed analysis of patterns and stylized facts reveals that exports of services are not only gaining strong momentum and catching up with exports of goods in many countries, but they could also trigger a new wave of trade globalization. Research applications of the trade in service dataset on structural transformation, resilience, labor reallocation, and income distribution are outlined.

Articles in the March 2015 Research Bulletin focus on the oil market, energy subsidies, and output. The Research Summary on "An Exploration in Deep Corners of the Oil Market," authored by Rabah Arezki, Douglas Laxton, Armen Nurekyan, and Hou Wang, examines fluctuations in oil prices. "The State Budget May Afford It All," by Christian Ebeke and Constant Lonkeng Ngbouana, reviews energy subsidies and their fiscal, distributional, and environmental costs. In the “Q&A” column Pau Rabanal takes a look at “Seven Questions on Potential Output.” The Bulletin includes a listing of recent IMF Working Papers, Staff Discussion Notes, recommended readings from IMF Publications, and a call for papers for the next Annual Research Conference. A link with information and free access to IMF Economic Review is also included.

This issue of the IMF Research Bulletin opens with a letter from the new editor, Rabah Arezki. The Research Summaries are a "Primer on 'Global Liquidity'" (Eugenio Cerutti, Stijn Claessens, and Lev Ratnovski); and "Trade Integration adn Business Cycle Synchronization" (Kevin Cheng, Romain Duval, and Dulani Senevirante). The Q&A column looks at "Seven Questions on the Global Housing Markets" (Hites Ahir, Heedon Kang, and Prakash Loungani). September 2014 issue of the Bulletin also includes updates on IMF Working Papers, Staff Discussion Notes, and Recommended Readings from the IMF Bookstore, as well as special announcements on new staff publications and the Fifteenth Annual Jacques Polak Research Conference. Also included is information on the latest issue of “IMF Economic Review” with a link to an article by Paul Krugman.