Too Much Finance, or Statistical Illusion?

Policy Brief
June 2015

For nearly three decades, the dominant view on the role of the financial sector in economic development has been that greater financial depth facilitates faster growth. However, the Great Recession has shaken confidence in that view because of the contributing role of high leverage and such financial innovations as collateralized subprime mortgage-backed assets and derivatives on them. Recent studies from the International Monetary Fund and Bank for International Settlements have argued that "too much finance" reduces growth. In an environment of new doubts about finance following the Great Recession, these studies finding that there can be too much of it seem to have struck a responsive chord. Cline warns that these findings should be viewed with considerable caution. He first shows that correlation without causation could similarly lead to the conclusion that too many doctors spoil growth, for example. He the demonstrates algebraically that if the variable of interest, be it financial depth, doctors, or any other good or service that rises along with per capita income, is incorporated in a quadratic form into a regression of growth on per capita income, there will be a necessary but spurious finding that above a certain point more of the good or service in question causes growth to decline. In some situations, finance can become excessive; the crises of Iceland and Ireland come to mind. But it is highly premature to adopt as a new stylized fact the recent studies' supposed thresholds beyond which more finance reduces growth.

Data disclosure: The data underlying the figures in this analysis are available here [xlsx].