After reading a post by Mike Mandel noting a decline in the share of college grads with a doctorate (and a decline in PhD’s real income over the past decade) I saw a comment from emawkc questioning whether advanced degrees really drive innovation and pointing to Bill Gates and Steve Jobs as posterchildren of under-educated innovators.
So, are Bill and Steve exceptions to the rule or are extra letters after a person’s name uncorrelated with innovation? Well… as much as it pains me to say (not having a PhD myself), when it comes to output measures of innovation (papers and patents) the PhD matters. It should be clear that this is the case in terms of academic publications, but I wasn’t sure about patents until after I did a little research of my own. I found two papers that looked at characteristics of named inventors on patents in different countries and in both cases PhDs were greatly overrepresented in the sample of inventors (that is, the percentage of inventors with PhDs was greatly larger than the share of the workforce with PhDs). Here are links to PDFs of the two papers:
Who Invents?: Evidence from the Japan-US Inventor Survey (Walsh and Nagaoka) – 45% of US inventors in their sample have a doctorate. According to the 2000 Census only 1% of persons 25 or older have a doctorate.
“Stacking” or “Picking” Patents? The Inventors’ Choice Between Quantity and Quality (Mariani and Romanelli) – 33% of inventors in their sample have a PhD. The countries in the sample were Germany, Italy, the Netherlands, and UK.
Of course correlation does not imply causation. I still do not believe that a PhD makes a person inventive–but inventive people are probably more inclined to get advanced degrees because academic research is both an outlet for creativity and a means of gathering skills needed in many fields to be both inventive and successful.