Table 3.

Power to detect A × E in the presence of A × C, and power to detect A × C in the presence of A × E when data is simulated under Purcell’s univariate moderation model

Cor. within Twins	Main effect mod	Effect G × E	ACE–A × E–A × C
			A × E	A × C
0	Small	Small	0.92	0.24
		Medium	0.79	0.39
		Large	0.72	0.76
	Medium	Small	0.99	0.21
		Medium	0.99	0.21
		Large	0.98	0.05
	Large	Small	1.00	0.19
		Medium	1.00	0.23
		Large	1.00	0.22
0.5	Small	Small	0.51	0.22
		Medium	0.37	0.57
		Large	0.49	0.92
	Medium	Small	0.72	0.14
		Medium	0.60	0.40
		Large	0.52	0.46
	Large	Small	0.85	0.15
		Medium	0.77	0.25
		Large	0.76	0.38
0.7	Small	Small	0.29	0.31
		Medium	0.26	0.73
		Large	0.44	0.94
	Medium	Small	0.33	0.33
		Medium	0.29	0.74
		Large	0.29	0.78
	Large	Small	0.44	0.44
		Medium	0.31	0.72
		Large	0.29	0.86
1	Small	Small	0.22	0.30
		Medium	0.54	0.75
		Large	0.75	0.93
	Medium	Small	0.18	0.66
		Medium	0.47	0.95
		Large	0.49	0.98
	Large	Small	0.15	0.94
		Medium	0.37	1.00
		Large	0.46	1.00

Cor within twins correlation between the twin 1 and 2 scores on the moderator variable