If you had two programmers competing for a job, equally qualified, but one who was 25 and the other 55, how would you choose?
What's equally qualified mean? I don't see how someone with less than 10 years of experience could possibly be equally qualified as someone with 30+ years of experience.
Either the veteran guy has a greater depth of skills and experience, or he's on a fast downward slope and not picking up new skills. If a 55 year old is bringing the same to the table as a 25 year old, the 25 year old is amazingly talented, or the 55 year old has abandoned learning new stuff.
Edit: or whatever age would result in equivalent industry experience
I don't know how you make the argument that the candidates are otherwise equal unless one has a resume item reading: 1970-2000: Coma, Mayo Clinic
So if I'm looking at succession, I'm probably going young. If I'm looking for someone with enough sense to avoid re-inventing the wheel, I'm probably going mature.
[all of which is somewhat irrelevant to the effects of unemployment].
1. In the US...
But AFAIK, hiring the older worker on the basis of age would never be illegal. Discriminating against an older candidate is illegal in certain circumstances, but not always.
http://www.eeoc.gov/facts/age.html
In practice, such discrimination appears to be commonplace and virtually unpunished given the burden on the candidate to prove that discrimination actually occurred.
Considering that there were 22,000 Federal age discrimination claims in 2009 [http://www.eeoc.gov/eeoc/statistics/enforcement/charges.cfm] and that 61% of all claims were considered to have no reasonable cause and 17% were closed administratively [http://www.eeoc.gov/eeoc/statistics/enforcement/all.cfm] one could napkin estimate that about 5000 people had some success in claiming age discrimination. I'd be willing to bet that most of those successes were against an employer and not related to the hiring process.
Not that any of that makes it right.
So when you find someone good at code, you want to make sure to move them out of coding when possible and into something that skill and understanding of programming has no bearing on: management. [edit: removed pointlessly antagonistic remark]
2. Without opportunity for advancement, your best young talent will apply to YC.
3. Having managers which understand the technical aspects of the projects they manage, doesn't hurt.
Of course, creating your own companies is the other way to get around this.
In my case, I was able to unintentionally run a bit of an experiment: starting around 35 or so I found it harder and harder to get work ... until I scrubbed my resume of all evidence of my age, which worked since I don't look my age and generally remembered to not talk about programming PDP-11s in interviews ^_^.
I did this in the middle of a job hunt and the change in responses was remarkable.