. Author manuscript; available in PMC: 2014 Apr 1.

Published in final edited form as: Dev Psychol. 2012 May 28;49(4):632–645. doi: 10.1037/a0028738

Table 2.

Regression Coefficients for Different Quality Groups Using the Developers’ and GAM-Derived Thresholds

Parameter	Developers’ Thresholds		GAM Thresholds
	T₁ = 3.0, T₂ = 5.0		T₁ = 3.8, T₂ = 4.6
	R² = 0.27, AIC = 3,653.2		R² = 0.28, AIC = 3,649.5
	Est.	Std. Err.	Est.	Std. Err.
ITERS:
Poor Quality group: 1 ≤ ITERS ≤ T₁ (comparison)
Transitional Quality group: T₁ < ITERS ≤ T₂	1.35	1.23	0.48	1.07
Good Quality group: T₂ < ITERS ≤ 7	2.79	1.40	2.66 ^*	1.09

Notes.

These models controlled for all the covariates used in Table 1.

T₁ is the lower threshold and T₂ is the upper threshold, which varies by the method used to select the thresholds.

AIC denotes the Akaike Information Criteria for model comparison.

p < .05.

^**

p < 0.01.