I think that assessing technical talent is fundamentally different than other types of talent, because technical stuff can be measured more effectively, and talent for writing code or designing and then implementing an architecture is also easier to measure than, say, social skills.
However, there are other aspects that we should not underestimate:<p>1) How well this person works in a team?
2) What's his/her goal in life? Is he "done", and looking to "park" in a job until retirement? Or still very willing to learn a lot?
3) How professional is his work? I mean: does he write documentation, does he care about shipping software that is elegant and functional, etc.
Etc.<p>There are two companies that I admire for what they're doing in this field, at two different stages:<p>Gild.com - a very unique approach to measuring technical talent, by using a proprietary algorithm that takes your github, stack overflow, etc, mixes all up, adds some juice, and voilà: you have a score. A successful, estabilished company.<p>CloudAcademy.com - younger and smaller, they mix tech snippets, videos, and an amazing quiz system to assess your skills (currently focusing only on Cloud Computing stuff, e.g. AWS, Azure, Google Compute Platform, Rackspace, VMware vCloud Air). They also added practical labs.
What's interesting is that after 20-30 minutes of assessing your skills, they get a very clear picture of what you know and what you don't, which I believe is very hard.
(Disclaimer: I am an advisor and investor in the latter.)