Table 2.

Changes in retention by level of care

Level of Care	Improvement %/month	F	p-value	Estimated baseline	Estimated End	% change	Model
% continuation from session 1 to session 2
Overall	0.85	8.34	0.01	72.09	84.84	18%	L
Outpatient	0.74	3.64	0.08	63.08	74.12	17%	L
Intensive Outpatient	0.92	5.01	0.04	78.37	92.24	18%	L
Residential	1.00	2.39	0.11	74.40	89.34	20%	L
% continuation from session 1 to session 3
Overall	0.69	4.77	0.05	62.43	72.78	17%	L
Outpatient	0.54	6.69	0.20	46.20	54.28	17%	L
Intensive Outpatient	0.52	1.22	0.29	74.14	82.01	11%	L
Residential	1.07	2.06	0.14	66.58	82.71	24%	L
% continuation from session 1 to session 4
Overall	0.39	1.44	0.25	54.17	60.02	11%	L
Outpatient	−0.43	0.95	0.35	35.30	28.85	-18%	L
Intensive Outpatient	0.34	5.36	0.02	80.79	85.88	6%	Q
Residential	1.00	1.83	0.16	61.54	76.47	24%	L

In the Model column, Q means quadratic trend model and L linear trend model. P-values are based on F statistics for regression models with degrees of freedoms of 1 and 13 for linear trend model and 2 and 12 for quadratic trend model. Baseline estimated for October 1, 2003; end date was December 31, 2004.