Since the entire experiment was based on an assumption that the subject would answer the appropriate question as soon as a part of the DFD was comprehended and understood. The order of questions as presented to each subject should not affect the comprehending sequences. Correlations between the answering order and the order of the questions presented on the sheet were 0.533 and 0.33 for the novices and intermediates, respectively. The two were of no statistical differences. The correlations did not suggest much interference by the presentation order of the questions and therefore the data could be used to represent the comprehension sequences of the subject.
The intermediate group took an average of 47.8 minutes to complete the entire DFD session, significantly shorter than the average of the novice group, 81.4 minutes (p<0.001). Analysis of variance was performed on the time used to complete each question. The effect of experience (novice/intermediate) was significant on the time used to complete each question (p<0.001). The depth level of the questions in the DFD did not appeared to affect the completion time of each question. The number of errors made during the entire experiment session was smaller for the intermediate group than for the novice group (p<0.001). These time and error differences showed that the two groups were indeed different in terms of their expertise in reading the DFD.
As far as the difference in comprehension strategy is concerned, there were also differences between the two groups. There were two counterparts of the comprehension strategy, one is the reading sequence, with which the subject looked through the DFD, and the other was the answer sequence, with which the question was picked and answered. Although the subject was asked to answer the question as soon as any part of DFD was understood, there was no guarantee that this could be exactly followed. Therefore, the data of the two counterparts were both looked at.
The average reading depth was computed as the levels reached into the diagram for each same direction move before turning back. There was significant difference between the two groups (p<0.05). The mean depth was 1.9 and 1.72 levels for the intermediate and the novice group, respectively, indicating that the experienced subject tended to go deeper into the diagram at each same direction move. The number of downward moves in reading along the DFD was also significant with 50.8 moves for the novice and 36.7 for the intermediate (p<0.05). This indicated that the intermediate used fewer steps in getting what he needed to learn from the DFD.
Each question had a correspondent level within the DFD. Similar to the definition of the reading depth, the average answering depth was the correspondent level reached during each same direction move when the question