Content quality of answers from the Dutch language zone during the early and later period of the ECORN-CF system. Ten expert answers from the early period (1-10) and ten expert answers from the later period (11-20) were assessed. Each column represents the mean of the four scores given to a single answer (one additional rater scored only the formal quality). The squares represent the highest and lowest scores given to that answer. The blue columns at the end of each group of ten expert answers represent the mean of the scores for all answers of the early period and the later period, respectively; they did not differ between early and later period (p = 0.095). Dark grey columns represent answers with a mean score of "good" quality.