Table 3.

Multilevel Growth Models Examining Five-Year Cognitive Change

Fixed Effects	Reasoning		Memory		UFOV		Digit Symbol		Vocabulary
Predictor Variable	B	t	B	t	B	t	B	t	B	t
Within-person
Linear Time	0.17	1.69	−0.10	−2.06*	−0.22	−1.50	−0.08	−1.96*	0.02	0.38
Quadratic Time	0.05	1.02	−0.04	−1.99*	−0.19	−2.67**	−0.05	−2.50**	0.02	0.87
Retest	0.28	2.25*	−0.07	−1.11	0.48	2.59**	0.06	1.27	0.07	1.31
Between-person
Age	−0.13	−9.27**	−0.06	−11.42**	−0.18	−12.52**	−0.05	−9.85**	0.01	1.82
Gender	0.20	1.10	0.50	7.81**	−0.11	−0.63	0.26	3.79**	0.11	1.55
Education	0.29	9.13**	0.09	8.53**	0.13	4.24**	0.07	6.18**	0.14	11.30**
Health	0.02	5.10**	0.01	3.82**	0.01	3.07**	0.01	5.31**	0.00	2.92**
African American (AA)	−1.49	−6.12**	−0.62	−6.88**	−1.15	−4.45**	−0.59	−6.26**	−0.75	−7.89**
Interactions
Linear Time x AA	−0.11	−1.47	0.03	0.89	0.12	1.09	0.02	0.82	−0.01	−0.28
Quadratic Time x RaceAA	−0.07	−2.13*	0.03	1.74	0.08	1.79	0.02	1.49	−0.01	−0.52
Random Effects
Predictor Variable	variance	Z	variance	Z	variance	Z	variance	Z	variance	Z
Linear Time	0.03	4.70**	0.00	3.85**	−0.03	3.51**	0.00	5.14**	0.00	0.97
Quadratic Time	0.00	0.31	--a	0.00	--a	0.00	0.00	0.51	0.00	2.53**

Notes:

^*p < 0.05,

^**p < 0.01;

^aVariance too small to be estimated- The final Hessian matrix was not positive definite although all convergence criteria were satisfied. AA = African American (reference group is White); UFOV = Useful Field of View. In addition, all models included study site and an indicator of when in time data collection occurred (replicate). These covariates are not shown for presentation simplification. There were no hypotheses about site and replicate effects, but they were a substantial identifiable source of participant variation. These effects, along with degree of freedom and standard error information for each effect, are available upon request.