I've tweeted an interesting chart at https://twitter.com/DuncanChapple/status/1000342565655334913

Using data from the FT's MiF ranking, I have compared alumni's rating of their careers services with their percentage increase in salary. The correlation, shown by the trend line, is so modest it's hardly worth discussing. However one interesting observation is that some of the schools with the highest-ranked careers services actually produce rather modest salary increases, as Glasgow, ESCP and Frankfurt,

My hypothesis is that these schools might be especially good a helping people get into new challenging areas where they might be relatively weak candidates. Their progress might not be above average, but that's the career transition they were aiming for.

Any other possible explanations?