Does industrial concentration impact on the relationship between policies and volatility?

It is usually recommended that countries diversify their economies to guard against any negative shocks that might impact on one industry. However, previous research has not identified how concentration can impact on the effectiveness of macroeconomic policies. This paper attempts to evaluate the relationship between industrial concentration, policies and economic volatility for a sample of 147 countries for the period 1970 to 2005. The study reports that less concentrated countries tend to have lower rates of output, consumption and investment growth volatility. In addition, while trade and capital account openness variables alone tend to diminish economic volatility, in concentrated economies opening both the capital and trade account can increase economic volatility.