Table 2

Level 1 Model Statistics for BSI GSI Global Scores to Determine Best Fitting Change Function

Model Estimated−2LLRAIC
Cubic polynomial: Int, T1, T2, T3 random*387.87417.87
Cubic polynomial: Int, T1, T2 random387.70411.70
Cubic polynomial: Int, T1 random407.92425.92
Cubic polynomial: Int random442.20456.20
Quadratic polynomial: Int, T1, T2 random391.71413.71
Quadratic polynomial: Int, T1 random411.52427.52
Quadratic polynomial: Int random445.38457.38
Logarithmic Model: Int, TLN random387.68401.68
Logarithmic Model: Int random488.72498.72
Linear: Int, T1 random425.94439.94
Linear: Int random458.39468.39
Intercept-only model (no change)521.46529.46
  • −2LLR, log likelihood ratio statistic; AIC, Akaike's information criterion: smaller values are better. Int, Intercept coded so it is an estimate of BSI GSI at first assessment period. T1, Time coded for linear function. T2, Time squared coded for quadratic function. T3, Time cubed coded for cubic function. TLN, Time coded for logarithmic function. Time is number of months since initial assessment.

  • * Hessian matrix was positive definite although all convergence criteria were met.