Table 2.

Intraclass correlations between scores on the first and second tests for each subscale and questionnaire (n = 368)

Questionnaire (months)	n	Communication	Gross motor	Fine motor	Problem solving	Personal–social
ICC for non‐imputed data
6	29	0.85	0.75	0.72	0.81	0.85
12	12	0.96	0.97	0.87	0.85	0.87
18	36	0.78	0.96	0.81	0.71	0.68
24	22	0.94	0.92	0.84	0.67	0.74
30	43	0.93	0.89	0.65	0.89	0.93
36	48	0.90	0.78	0.72	0.76	0.86
42	22	0.86	0.95	0.88	0.71	0.78
48	17	0.81	0.78	0.83	0.87	0.86
54	19	0.81	0.93	0.90	0.96	0.94
60	33	0.85	0.82	0.91	0.90	0.93
ICC for imputed data
6	34	0.75	0.75	0.76	0.81	0.87
12	13	0.97	0.97	0.87	0.84	0.90
18	38	0.79	0.95	0.81	0.72	0.68
24	26	0.93	0.92	0.88	0.75	0.76
30	54	0.90	0.91	0.62	0.87	0.91
36	56	0.91	0.81	0.74	0.80	0.88
42	28	0.86	0.94	0.79	0.77	0.79
48	23	0.81	0.76	0.86	0.83	0.87
54	21	0.79	0.85	0.85	0.97	0.94
60	39	0.83	0.80	0.92	0.86	0.92

Numbers of participants were larger for ICC of the imputed datasets because data with missing items were excluded when a dataset was not imputed. ICC, intraclass correlation.