Unfortunately, the original version of this article [1] contained two mistakes. The text on page 5 reading, “Floor effects were negligible for all items (2 %–14 %) while substantial ceiling effects were observed except Item 4 (30 %–40 %)” should instead have read, “Floor effects were negligible (2 %–14 %) while substantial ceiling effects were observed for all items (30 %–40 %) except Item 4”.

In Table 5 (Table 1 here), there is a mistake in the ordering of items. The corrected table can be seen below.

Table 1 Distribution in percentage on the lowest and highest rating scale for the items
Full size table