[bcheung]

Based on the findings I think it is premature to say this is ageism.

There are multiple other factors going on here:

1) As senior developers become more skilled there is a diminishing return in terms of compensation. This happens regardless of age. A developer with 40 years of experience is not really worth that much more than a developer with 30 years of experience.

2) As developers get nearer towards retirement there is less incentive for them to stay at the top of their field.

3) As developers get older they tend to want to find a place they enjoy working at rather than playing the salary game every 2 years.

[bduerst]

True, but it should be easy to control for this right? Check the progression in other skilled fields and cross reference into tech.