Table 2. Orthogonal contrast coding of categorical predictors in the SRT, VSL and A-NADL tasks.
| Task | Predictor | Contrast coding | Purpose |
|---|---|---|---|
| SRT | Block (Bl) | 1: Bl 6 = -2/3, Bl 5 and 7 = +1/3 | RQ 1 |
| 2: Bl 5 = -1/2, Bl 7 = +1/2 | Exploratory | ||
| Group | TD = -1/2, DD +1/2 | RQ 2 | |
| VSL | Element (El) | 1: El 1 = -2/3, El 2 and 3 = +1/3 | RQ 1 |
| 2: El 2 = -1/2, El 3 = +1/2 | Exploratory | ||
| Group | TD = -1/2, DD +1/2 | RQ 2 | |
| Triplet Set (TS) | TS A = -1/2, TS B = +1/2 | Exploratory | |
| Random Order (RO) | RO 1 = -1/2, RO 2 = +1/2 | Exploratory | |
| A-NADL | Block (Bl) | 1: Bl 4 = -2/3, Bl 3 and 5 = +1/3 | RQ 1 |
| 2: Bl 3 = -1/2, Bl 5 = +1/2 | Exploratory | ||
| Grammatical | No = -1/2, Yes = +1/2 | RQ 1 | |
| Group | TD = -1/2, DD +1/2 | RQ 2 | |
| Generalization | No = -1/2, Yes = +1/2 | Exploratory | |
| Target Type | Target = -1/2, Non-target = +1/2 | Exploratory | |
| Experiment Version | Lut = -1/2, Mip = +1/2 | Exploratory |
Note: RQ = research question: RQ 1 pertains to the overall learning effect, while RQ 2 regards the effect of group (dyslexia versus control) when looked at in interaction with the effect of learning overall. Exploratory predictors and contrasts are included either because predictors are counter-balancing factors or because predictors need to be orthogonally coded (i.e. in the case of predictors with two contrast codings).