Encyclopaedia Britannica print sets sold

As solar panel costs plummeted, Encyclopaedia Britannica print sales also plummeted, a correlation of 0.978 that connects two things that were both made obsolete by the same decade: the encyclopedia by Wikipedia, the expensive solar panel by Chinese manufacturing. Both were premium products that became untenable as cheaper alternatives arrived. The volumes gather dust, the old panels gather inefficiency, and the chart records both declines with the nostalgia precision of a coefficient that remembers when knowledge and electricity were both expensive.

Britannica print sales declined from about 12,000 sets per year to zero by 2012 (when print was discontinued). Solar costs fell from about $4.00 to about $1.50 per watt during the same 2005–2012 window. Both are declining curves driven by disruption: Wikipedia killed the encyclopedia, and Chinese manufacturing killed the premium solar panel price. Eight data points, both declining, positive correlation (both going down).

Eight years of Britannica and solar costs is a correlation between two disruptions that happened simultaneously: one in knowledge distribution, one in energy technology. Both premium products were replaced by cheaper alternatives, and both curves declined at the same rate. The leather-bound set is discontinued, the panel price collapses, and both trends measure the same decade of creative destruction. The encyclopedia is closed. The factory scales. The price falls.