Ah well, its almost universally agreed amongst university lecturers that Scots students are poor in comparison to students from elsewhere in speaking up in tutorials. Scots schools are generally quite poor in this regard.
But how do you measure the claim in general? That Scots students go on to university and graduate with excellent degrees and so on against a meaningful comparator? How do we know that Scottish universities are providing a uniformly high quality of education? Theres rather a lot of them compared to similarly populated sized countries so it seems unlikely! What is a "well paid, professional level job"? Is it a job which requires a degree or one which requires a degree and membership of a professional association? What do we mean by "well paid"?
One way to measure it might be to look at the numbers of professional Scots who are recruited into well paid professional roles overseas compared to previous times. If that number is reducing, then it would be an indicator that the claim isn't being met. If its holding level of increasing, then it could be a valid claim. Successful business start ups (measured as profit making and innovation) as a measure of entrepreneurialship would be another way of measuring this.
You could also look at the number of Scottish schools which feed into Oxbridge, although this can be an unpopular measure now. Although in other countries Oxbridge remains a mark of success. (you can go very off topic on that one but it certainly used to be a criterion of success in some Scottish state schools). So if you dislike Oxbridge, you could look at how many Scottish schools are feeding into the most highly regarded Masters courses at European and American universities, as many students look outwith their home country for a Masters. You might not get that far with this one however as Masters degrees are relatively unpopular in the UK as a whole, and Scotland fits into this pattern, when compared to some European universities where they are almost a pre-requisite of professional employment.
What you really want to make sure about of course is that Scottish schools are not holding any pupils back by anything that they are doing or failing to provide, when compared with schools in other comparable countries.
What we do know is that university education in Scotland is in turmoil at the moment, with strikes being a continual irritant affecting the quality of university education, and that has been going on for some years now. The problem has not been resolved.
I was also struck by the claim above by MotherofMonkeys that wellbeing and equality are as much on the agenda as exam results. That doesn't sound all that compatible with the above claim and against its fairly unquantifiable, but isn't it society's job to provide these values and the schools to educate for exams? Where does "wellbeing and equality" end and political indoctrination begin?