Table 2.
Model Fit Indexes for Competing Models of DS, LNS, DS+LNS, and Verbal+Performance+Achieve Scores
| Separate Models of DS, LNS, DS+LNS, and Verbal+Performance+Achieve | |||||
|---|---|---|---|---|---|
| DS | |||||
| Model | L2 | df | p (Bootstrap) | LL | LL-based BIC |
| 1-continuous-factor | 1962.24 | 833 | 0.00 | −5835.17 | 11968.49 |
| 2-continuous-factor | 1384.57 | 817 | 0.00 | −5545.99 | 11498.54 |
| 3-continuous-factor | 1336.69 | 801 | 0.00 | −5522.05 | 11559.07 |
| 2-continuous-factor | |||||
| with constraints | 1388.84 | 826 | 0.00 | −5548.12 | 11441.82 |
| 2-discrete-factor (levels: 7, 6) | 1304.17 | 817 | 0.00 (0.13) | −5505.77 | 11418.10 |
| LNS | |||||
| Model | L2 | df | p (Bootstrap) | LL | LL-based BIC |
| 1-continuous-factor | 499.34 | 852 | 1.00 | −4057.20 | 8290.62 |
| 2-continuous-factor | 431.39 | 844 | 1.00 | −4023.42 | 8277.29 |
| 3-continuous-factor | 409.90 | 836 | 1.00 | −4012.48 | 8309.63 |
| 1-discrete-factor (levels: 9) | 375.87 | 845 | 1.00 (0.04) | −3995.46 | 8214.60 |
| DS+LNS | |||||
| Model | L2 | df | p (Bootstrap) | LL | LL-based BIC |
| 1-discrete-factor (levels: 8) | 7923.77 | 795 | 0.00 | −9852.72 | 20213.07 |
| 2-discrete-factor (levels: 7, 6) | 7197.93 | 778 | 0.00 | −9489.79 | 19602.29 |
| 4-discrete-factor | |||||
| (levels: 5, 6, 5, 5) | 6786.08 | 759 | 0.00 (0.72) | −9327.23 | 19319.36 |
| Verbal+Performance+Achieve | ||
| Model | LL | LL-based BIC |
| 1-continuous-factor | −7142.38 | 14345.72 |
| 1-discrete-factor (levels: 5) | −7109.78 | 14307.40 |
| Extended Models of Working Memory & Verbal+Performance+Achieve | ||
| DS & Verbal+Performance+Achieve | ||
| Model | LL | LL-based BIC |
| 3-discrete-factors (levels: 7, 6, 5) full | −14575.81 | 29658.94 |
| nested, STS-to-G path fixed | −14626.16 | 29752.88 |
| nested, Add. Ctrl-to-G path fixed | −14621.18 | 29742.92 |
| LNS & Verbal+Performance+Achieve | ||
| Model | LL | LL-based BIC |
| 2-discrete-factors (levels: 8, 5) full | −13063.78 | 26438.76 |
| nested, LNS factor-to-G fixed | −13214.74 | 26733.93 |
| DS+LNS & Verbal+Performance+Achieve | ||
| Model | LL | LL-based BIC |
| 5-discrete-factors (levels: 5, 6, 5, 5, 5) full | −18137.08 | 37139.06 |
| nested, STS-to-G path fixed | −18195.98 | 37250.97 |
| nested, GAC-to-G path fixed | −18168.51 | 37195.15 |
| nested, MS-to-G path fixed | −18130.79 | 37119.73 |
| nested, BO-to-G path fixed | −18141.97 | 37142.07 |
| nested, MS&BO-to-G paths fixed | −18133.36 | 37118.33 |
Note: DS: The Digit Span task. LNS: The Letter-Number Sequencing task.
Verbal+Performance+Achieve: Summary scores of the four WISC-R Verbal subscales, four WISC-R Performance subscales, and the total standard scores of Chinese and Mathematics achievement tests. STS: Short-Term Storage. Add. Ctrl: Additional Attention Control of the Digit Span task. G: The general factor of the Verbal, Performance, and the Achievement Total summary scores. GAC: The General Attention Control factor. MS: The Mental Sorting factor. BO: The Back-Ordering factor. Models with continuous indicators do not yield the chi-square (L2) index, and the L2-based bootstrapped p values for model fit are thus not available for models with the continuous Verbal, Performance, and Achieve indicators. As a result, the L2-based bootstrapped p values (displayed in parentheses) were only provided for the besting fitting DS, LNS, and DS+LNS models. All Bayesian Information Criterion (BIC) indexes obtained for model selections were derived from the log-likelihood (LL) values.