Table 3.1 Observers’ perceptions of leadership-related processes in the BBC Prison Study (data from Haslam & Reicher, 2007a)

	Guards		Prisoners
Measure	Day 2	Day 6	Day 2	Day 6
Group identity	3.80	2.30	2.50	5.60
Leadership	3.60	1.90	2.70	5.80
Group efficacy	4.00	1.80	2.70	5.50

Note: As the study progresses (from Day 2 to Day 6), the Guards’ group identity declines along with their leadership and efficacy as a group. Over the same period, the Prisoners’ shared identity, leadership, and group efficacy all increase.