TABLE 2.

Network Descriptive Statistics

	School 1 (N = 1193)		School 2 (N = 419)
Characteristic	Wave I	Wave II	Wave I	Wave II
% missing nominations	2.3	19.9	1.7	12.6
M friends nominated	2.0	1.8	3.4	3.2
Range of friend nominations made	0 – 10	0 – 10	0 – 10	0 – 10
Range of friend nominations received (popularity)	0 – 15	0 – 8	0 – 18	0 – 13
M, Range of popularity difference	5.4 (0 – 44)		10.4 (0 – 57)
Friend reciprocity index	.27	.34	.43	.42
Friend transitivity index	.21	.23	.24	.23
	School 1		School 2
M stable friendship ties	0.59		1.26
M new friendship ties	0.78		1.45
M friendship ties dissolved	1.04		1.74
Jaccard coefficient	.25		.28

Note. The reciprocity index is the proportion of friendship nominations that were reciprocated. The transitivity index is the proportion of 2-paths (friendship ties between AB and BC) that were transitive (friendship ties between AB, BC, and AC). The Jaccard index measures the amount of network change between consecutive waves, and expresses quantitatively whether the data collection points are not too far apart. Values of 0.3 or greater are ideal, so that assumptions that the network change process is gradual are met[22].