Friday, May 25, 2012

How Reliable Are the Social Sciences?

Gary Gutting shares some thoughts on this important question:
There is considerable distance between, say, the confidence we should place in astronomers’ calculations of eclipses and a small marketing study suggesting that consumers prefer laundry soap in blue boxes…

The core natural sciences (e.g., physics, chemistry, biology) are so well established that we readily accept their best-supported conclusions as definitive.  (No one, for example, was concerned about the validity of the fundamental physics on which our space program was based.)  Even the best-developed social sciences like economics have nothing like this status...

Social sciences may be surrounded by the “paraphernalia” of the natural sciences, such as technical terminology, mathematical equations, empirical data and even carefully designed experiments.  But when it comes to generating reliable scientific knowledge, there is nothing more important than frequent and detailed predictions of future events.  We may have a theory that explains all the known data, but that may be just the result of our having fitted the theory to that data.  The strongest support for a theory comes from its ability to correctly predict data that it was not designed to explain.

While the physical sciences produce many detailed and precise predictions, the social sciences do not.  The reason is that such predictions almost always require randomized controlled experiments, which are seldom possible when people are involved.  For one thing, we are too complex: our behavior depends on an enormous number of tightly interconnected variables that are extraordinarily difficult to  distinguish and study separately.   Also, moral considerations forbid manipulating humans the way we do inanimate objects.   As a result, most social science research falls far short of the natural sciences’ standard of controlled experiments.

Without a strong track record of experiments leading to successful predictions, there is seldom a basis for taking social scientific results as definitive…

Given the limited predictive success and the lack of consensus in social sciences, their conclusions can seldom be primary guides to setting policy.  At best, they can supplement the general knowledge, practical experience, good sense and critical intelligence that we can only hope our political leaders will have.
I am sympathetic to many of the points Gutting makes in this article.  However, there are also some important lessons from my own discipline of economics that are nearly indisputable that politicians often ignore.  These include comparative advantage and gains from trade, the law of demand, supply and demand analysis and market equilibrium, etc.  There are a number of policy issues that economists have strong agreement on.  Policy makers who ignore these concepts may cause harm to the economy and the citizens of their countries.

Having said that, I think Gutting makes some great points and generally agree that the social sciences have far less predictive power than the physical sciences.  This is not necessarily a weakness of the social sciences, but due more to the complexity of their object of study (humankind).  People are remarkably complex actors and don't follow predictable behavior the way non-intelligent particles and chemical compounds do.  This is what makes the social sciences so fascinating and so frustrating at times.  That is a feature and not a bug of the field.  The richness of humanity is that people are motivated by a myriad of incentives in their lives.  If all of human behavior could be explained with the precision of a ball in motion, we would live in a far less interesting world.

Both academics and policy makers are often guilty of over-representing the predictive power of the social sciences.  The social sciences have a lot to contribute to our understanding of human behavior, but the conclusions of their theories should be taken with a dose of humility and often a bit of skepticism.  Generally speaking, the more sophisticated the statistics required to identify an effect, the more wary I am of the findings.

For more on the limits of what social sciences (and politicians) can actually know, read Hayek's The Use of Knowledge in Society (PDF).  I cannot recommend this brilliant article highly enough.

See my previous post on Making Economics Relevant Again.

(HT Freakonomics)

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