Where the figures come from
Every check draws on our own and public sources: vacancies from our own network of local job boards, national statistics (CBS) pay data, the collective agreement you name, labour market figures from UWV and published salary surveys from trade bodies and sector funds. At least three independent sources, each with its origin and reference date.
We show the scope, not just the figure
A large sample usually covers a broad occupational group across the whole country, junior to senior mixed together. The national statistics office measures occupational groups, not individual roles. We say so in as many words. Such a source must not dominate the average.
The reference date is the source's date
Not the day of your check. If a source is older than about eighteen months, or has no reference date, we use it only as support and say so.
We never guess
No sample size on the page? Then it says "not stated". No collective agreement given? Then we do not go looking for one: another employer's pay scale in your report is worse than no scale at all.
Why it takes a minute
Because the searching really happens at that moment. Nothing comes from a stock list of standard salaries. The same question within a month does return the same answer from our cache.