Table 4.

Existing classification or problem scheme according to Van den Haak et al. (2007)

1. Comprehension	Participant finds that the information on the site is no clear or applicable: he or she experiences syntax problems; he or she finds the choice of vocabulary problematic.
2. Relevance	Participant feels that certain information should not be included or should be reduced.
3. Completeness	Participant feels that information is missing or more elaboration is needed.
4. Structure	Participant finds that the order of information is problematic or that the structure is not clearly signalled.
5. Formulation	Participant does not appreciate a particular formulation.
6. Graphic	Participant does not appreciate layout or illustrations.
7. Correctness	Participant detects a violation of syntax, spelling or punctuation rules.
8. Data entry	Participant does not know how to enter data on the site.
9. Visibility	Participant fails to spot a particular link, button or piece of information on the site.