Found in 2 comments on Hacker News
thomas · 2019-02-06 · Original thread
There are standardized tests for all this stuff, as you might imagine. One in this case would be the LM80 test.

Source: https://www.amazon.com/LED-Lighting-Primer-Future/dp/1449334...

thomas · 2013-09-18 · Original thread
Great comments here, and interesting article. If anyone is interested, here is a book on LED lighting: http://www.amazon.com/LED-Lighting-Primer-Future/dp/14493347...

covers all the basics - CFL lifespan, lumen depreciation, etc.

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