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Dave Stuhlsatz's avatar

Thanks for this post Brian. You touch briefly on the common problem with the construction innovations in your list--that they're lateral improvements on products, and have practically no impact on construction productivity. A fiberglass door takes as long to hang as wood door. In the case of vinyl windows, and by extension all modern clad-composite windows, proper installation actually requires an increase in labor inputs. PEX is a little faster to install than copper, but any productivity gain gets more than canceled when homebuyers demand more plumbing fixtures.

In theory, SIPS offer the most productivity gains on overall shell construction, but they create an additional planning burden on design and site management. They also can slow down some of the trades because of the challenges associated with running wiring and plumbing.

In my brief career in single family home architecture the highest impact innovation has probably been LED lighting. Even in that area, easier and faster installation hasn't moved the needle on construction costs or speed.

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gregvp's avatar

There is quite an extensive literature about the diffusion of innovations sitting at the intersection of the disciplines of economic history, and productivity studies within economics (JEL code D24, mainly). Being economists, the economists often look at proxies like patents and royalties rather than directly at individual innovations, though. The historians are better.

Vaclav Smil has summarised some research about the time required for innovations, with a focus on what he calls "prime movers", augmentations of muscle power such as wind power, water power, steam engines and turbines, electric motors, internal combustion engines and jet turbines.

His recent book "Grand Transitions" covers these, although I found his earlier "Energy In Nature and Society" to be better for some of them. The latter book also has charts of (USA) adoption curves for telephones (landlines), radios, refrigerators, color TVs and more.

In almost every case the adoption cycle falls into this 20-to-40-year duration that you have identified. Some of his innovations, like nuclear power, also saturate well below 100%.

Incidentally, the tractor is not a good example of an innovation for reasons of new capabilities. Pretty much everything that tractors did initially--pulling things, ploughing, harrowing, seeding, etc.--was done with horses and horse-powered machinery beforehand. In "Energy In Nature and Society" there is a photo of a team of 20 horses pulling a McCormick combine harvester. Tractors were also preceded by traction engines -- the same thing, except steam powered and consequently larger and heavier. New capabilities--front-end loaders, spraying equipment, etc.--came after tractors were established. Initially a tractor was a low-latency, tireless horse: you didn't have to spend an hour fetching it and harnessing it before starting work, nor did you have to manage its workload so carefully.

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