Talent Development is about two things, (1) improving proficiencies in skills we already have and (2) adding or acquiring new skills. This means that we need tracking (and even better measurement) of proficiencies in skills. The simplistic way of years of experience is not good enough. We all have multiple skills and our proficiencies vary in the different skills. How can we possibly use one number to indicate our proficiency?
Of course, now comes the problem of measurement. We all desire very scientific and objective measures to things. However, the reality is that not everything can be measured objectively and with a universally common scale. Of course, height, weight, etc. have a common universal scale. What about happiness, beauty, satisfaction? Yet we need some way of indicating the proficiencies here.