Path dependence

While researching a chapter on railroad gauge standards for my book on the history of technology standards I was overwhelmed with the persistent urban legend that the standard gauge of 4′ 8.5″ is derived from the span of the wheels on a Roman war chariot.

It’s amusing how many technology columnists (usually writing in the IT trades) and keynote speakers have propagated this cute piece of misinformation and all deliver the same punchline that the space shuttle travels to its launch pad on rails derived from a standard set by a “horse’s ass.”

The true basis of the standard — which was based on the width of a Welsh mine’s rails and adopted by English railroad pioneer George Stephenson in 1810 — is not so interesting as the story of its spread throughout Great Britain and across the Atlantic to the United States. I was intrigued to learn that the standardization of gauges is the basis of the economic theory of “path dependence,” which posits that technology adoption is tied to the inertia of history more than specific attributes. Example: driving on the left or right side of the road. The issue isn’t why one country selected one side or the other, but the persistence of the two approaches is assured by the immense switching costs over time. In other words, a “bad” standard will live on if the cost of switching to a “good” standard is too high.

It took an act of Parliament to standardize track gauges in Great Britain as a matter of national economic interest and efficiency. In the U.S. it was the lessons of the Civil War that pushed the South to standardize its incompatible system of three incompatible gauges to the north’s 4′ 8.5″
over a single Memorial Day weekend in the 1880s. Path dependence theory says standardization of incompatible standards will occur when the economic benefits hit a critical point where cooperation and interconnection is to the advantage of all participants.

I wonder what current information technology standards live on due to path dependence. QWERTY keyboards? The Navy tested and learned that switching typists to the Dvorak system yields an efficiency payback within ten days, yet, I still type away on good old QWERTY.

Author: David Churbuck

Cape Codder with an itch to write