TABLE 4.
Changes to various original models (from Zoccolotti et al., 2020) when a new predictor is added.
| Added predictor | Original Model | % R2 original model | % R2 with the added predictor | Un. | Com. | Tot. | % R2 Tot | % R2 Un. | Variance shared with |
| Arithmetic Facts (AF) | Reading (fluency) | 48.7 | 48.9 | 0.003 | 0.29 | 0.29 | 59.7 | 0.6 | OD (14%); OD and V-ApwM (16%) |
| Spelling | 29.2 | 30.9 | 0.02 | 0.08 | 0.10 | 32.7 | 5.7 | OD (18%); OD and SpwR (16%) | |
| Orthographic Decision (OD) | Calculation (speed) | 37.9 | 38.2 | 0.004 | 0.16 | 0.17 | 43.4 | 1.0 | AF (12%) |
| Calculation (accuracy) | 27.5 | 28.9 | 0.01 | 0.16 | 0.17 | 60.2 | 4.7 | NO and AF and CS (16%) | |
| RAN | Calculation (speed) | 37.9 | 40.2 | 0.02 | 0.13 | 0.15 | 38.0 | 5.8 | AF (23%) |
| Calculation (accuracy) | 27.5 | 29.1 | 0.02 | −0.01 | 0.002 | 0.6 | 5.4 | – | |
| Spelling | 29.2 | 29.2 | 0.000 | 0.001 | 0.001 | 0.5 | 0.03 | – | |
| Computation Strategies (CS) | Reading (fluency) | 48.7 | 53.4 | 0.05 | 0.18 | 0.23 | 42.6 | 8.9 | OD (18%) |
| Spelling | 29.2 | 29.6 | 0.004 | 0.08 | 0.08 | 26.9 | 1.2 | OD (10%); OD and SpwR (15%) | |
| Repetition of Pseudo-word Series (RpwS) | Reading (fluency) | 48.7 | 50.1 | 0.01 | 0.17 | 0.18 | 36.8 | 2.8 | OD (10%) |
| Calculation (speed) | 37.9 | 38.5 | 0.01 | 0.03 | 0.03 | 8.9 | 1.6 | – | |
| Calculation (accuracy) | 27.5 | 28.6 | 0.01 | 0.09 | 0.10 | 36.6 | 3.6 | NO and AF and CS (11%) | |
| Visual-auditory Pseudo-word Matching (V-ApwM) | Calculation (speed) | 37.9 | 37.9 | 0.000 | 0.08 | 0.08 | 21.5 | 0.1 | AF (11%) |
| Calculation (accuracy) | 27.5 | 28.6 | 0.01 | 0.07 | 0.08 | 27.0 | 4.0 | – | |
| Spelling | 29.2 | 29.6 | 0.004 | 0.007 | 0.01 | 2.2 | 1.2 | – | |
| Number Order (NO) | Reading (fluency) | 48.7 | 48.8 | 0.001 | 0.06 | 0.06 | 12.1 | 0.3 | – |
| Spelling | 29.2 | 30.8 | 0.02 | 0.12 | 0.14 | 43.8 | 5.3 | OD (16%); OD and SpwR (21%) | |
| Single Pseudo-word Repetition (SpwR) | Reading (fluency) | 48.7 | 48.8 | 0.001 | 0.08 | 0.08 | 16.4 | 0.03 | – |
| Calculation (speed) | 37.9 | 37.9 | 0.000 | 0.04 | 0.04 | 11.2 | 0.000 | – | |
| Calculation (accuracy) | 27.5 | 27.6 | 0.001 | 0.02 | 0.02 | 5.9 | 0.02 | – |
The first column indicates the added predictor; the second the original model; next, the total percentage of variance (R2) explained by the original model is presented (from Zoccolotti et al., 2020), followed by the indication of the total variance (R2) explained by the same model after the addition of the predictor. Then, unique, common and total contributions of each added predictor are presented (as raw beta coefficients). The next columns report the% of total and unique variances (R2) accounted by the added predictor with respect to the total variance explained by the model. The last column reports the list of predictor(s) with which the added predictor shared variance (in excess of 10%).