Moore's Law, the much-cited theory that rates of technological improvement increase exponentially over time - is true, say MIT researchers.
But it's not the best prediction for the pace of technological progress, with that honor going to the less well-known Wright's Law, which was first formulated in 1936 and holds that progress increases with experience - specifically, that each percent increase in cumulative production in a given industry results in a fixed percentage improvement in production efficiency.
Some of the results were surprising, says assistant professor of engineering systems Jessika Trancik, and could help industries decide where to focus their research and help investors pick high-growth sectors.
To carry out their analysis, the researchers amassed an extensive set of data on actual costs and production levels over time for 62 different industry sectors; these ranged from commodities such as aluminum, manganese and beer to more advanced products like computers, communications systems, solar cells, aircraft and cars.
"There are lots of proposals out there," Trancik says, for predicting the rate of advances in technologies. "But the data to test the hypotheses is hard to come by."
The research team scoured government reports, market-research publications, research reports and other published sources to compile their database. They only used sources for which at least a decade's worth of consistent data was available, and which contained metrics for both the rate of production and for some measure of improvement. They then analyzed the data by using the different formulas in "hindcasting": assessing which of the formulas best fit the actual pace of technological advances in past decades.
"We didn't know what to expect when we looked at the performance of these equations relative to one another, but some of the proposals do markedly better than others," says Trancik.
The rates of change vary greatly among different technologies.
"Information technologies improve the fastest, but you also see the sustained exponential improvement in many energy technologies. Photovoltaics improve very quickly," says Trancik. "One of our main interests is in examining the data to gain insight into how we can accelerate the improvement of technology."