An analysis of peer, self, and tutor assessment in problem-based learning tutorials

Figures & data

Figure 1. The final 17-item draft of the Peer assessment instrument.

Figure 2. Diagram showing the sequence of marking episodes and assessment events for each student in each of 13 tutorial groups.

Table 1.  Descriptive statistics–self-, peer-, and tutor assessment - for each of the two marking episodes

Marking episode	Score	Number of responses	Mean	Standard deviation	Minimum–maximum score
1	Self-assessment	108	68.80	8.32	44–85
1	Averaged peer-assessment	115	79.08	4.21	66–85
1	Tutor assessment	89	76.15	7.58	43–85
2	Self-assessment	82	67.70	10.70	38–85
2	Averaged peer-assessment	87	79.04	3.75	68–84
2	Tutor assessment	70	74.99	8.96	46–85

Figure 3. Bland-Altman plot of self-assessment versus tutor scores at time 2.

Figure 4. Bland-Altman plot of peer-averaged versus tutor scores at time 2.

Table 2.  Correlation between pairs of scores obtained from self-, peer-, and tutor assessment. Peer averaged scores have been used. Cronbach's alpha for all peer averaged scores across 13 tutorial groups in the first marking episode = 0.77, while Cronbach's alpha for all peer averaged scores across 13 tutorial groups in the second marking episode = 0.66

Marking episode	Paired scores	Number of paired responses	Pearson correlation coefficient	p value (2 tailed)
1	Self and tutor scores	85	0.41	<0.001
1	Self and peer-averaged scores	108	0.32	<0.001
1	Tutor and peer-averaged scores	89	0.40	<0.001
2	Self and tutor scores	66	0.31	0.012
2	Self and peer-averaged scores	82	0.30	0.007
2	Tutor and peer-averaged scores	70	0.60	<0.001

Figure 5. Box plots of averaged peer-assessment scores for thirteen tutorial groups with results obtained from the first marking episode.