All students progress at different speeds. The reference to the “first four years of piano lessons” therefore applies to an average student with average talent who practises regularly.

The beginner level is divided into ten stages, while the intermediate and advanced levels each have only five – so we have 20 different levels in total. 

What matters most: the difficulty level assumes that a student can learn the piece within one week to one month and then perform it at the correct tempo without major mistakes. It is, of course, possible that students could manage much more difficult pieces if they play far below the original tempo, leave out some notes, or practise the same piece for half a year – this is not what the scale is meant to reflect.