In the Dutch salary system, how do the "steps" ("trede") work? The salary system in Dutch academia is based on a number of "scales" (schaal), which are related to the different academic ranks. The salary in the same scale can vary considerably, depending on the "step" (trede) on which the employee is positioned  (see the current salary table). In job offerings, the scale is usually specified in the job advertisement, whereas the step depends on the candidate and can be subject to negotiation. 


How does one rise in "steps"? Is it bound to certain achievements, or does it happen automatically after a certain time (what are the time intervals in this case)?
How is the starting step for a new employee usually determined?
You automatically go up one step per year, until you reach the top of the scale. Starting points are determined by HR, based on an estimate of how many 'years' into the scale you already should be. For example, a postdoc would typically begin on (I think) 10-4, to account for the time spent doing the PhD (note that the Promovendus - PhD student - scale P matches the start of scale 10).

I imagine that it is theoretically possible to refuse someone an increment, or advance them by several steps at once - but I've never heard of it actually happening.

Once you hit the top of a scale, you're stuck there until you can get promoted to the next scale (which requires an explicit process to be followed).

(The other quirk of the Dutch system is that your annual salary is typically 14x the number in this table: 12 monthly payments, plus a vacation payment and an annual bonus.)