It always confused me that some really bright young people (e.g., Zuckerberg) can't grasp this: the variation in intelligence and capability due to non-age factors >>> the variation in intelligence and capability due to age factors.
Put another way, I'd take Einstein in his 40s over a thousand other randomly-chosen physicists in their 20s
> I'd take Einstein in his 40s over a thousand other randomly-chosen physicists in their 20s
(I don't think I've seen a more clear example of a false dichotomy.)
I agree that age is rarely the determining factor for someone's general competence: someone who's competent young is going to be competent when they're older. Their strengths do shift slightly, though.
Depending on the mission, experience may extremely valuable; when breaking new ground, sometimes creativity and energy are more important. It's hard to argue that there's no correlation with age there over a person's life, even if it's relatively minor.
Ageism to me seems a lot like sexism, racism, and every other -ism. The error is to use those characteristics as false metrics for someone's competence: e.g. "you're old, therefore you're slow" or "you're young, therefore you don't know what you're talking about". Let their work speak for itself and see if they're the right fit for the job at hand. The fact that there are age biases due to the type of work isn't always indicative of discrimination, though it often is.
(In Zuckerberg's case, I would be unsurprised to hear about discrimination given his YC07 talk about "hiring young").
If it's mainly selection based on metrics of certain types of competence and strengths that may correlate with age, then we shouldn't be hearing stories about people having to shave or dye their hair, get a hipster-wardrobe, just to have a chance at getting a second interview. (or plastic surgery ...)
Put another way, I'd take Einstein in his 40s over a thousand other randomly-chosen physicists in their 20s