Table 5.
Power calculation
| Outcome measure | δ expected difference in mean | σ expected standard deviation | α | Power | Reference |
|---|---|---|---|---|---|
| Days to first employment or beginning of education | 68 | 45 | 0.0125 | 1.000 (t test) | Bond et al. [8] (2008), |
| Cognitive function | 0.3 | 0.7 | 0.0125 | 0.989 (t test) | McGurk et al. [13] (2005) |
| The Brief Assessment of Cognition in Schizophrenia [32] | |||||
| Function measured with Personal and Social Performance (PSP) scale [31] | 7 | 14 | 0.0125 | 0.999 (t test) | Kawata et al. [31] (2008). Nasrallah et al. [46] (2008) (No IPS studies use PSP scale. δ is estimated) |
| Self-efficacy measured with General Self-Efficacy scale [37] | 0.28 | 0.85 | 0.0125 | 0.880 (t test) | Tsang et al. [14] (2010) |
| Self-esteem measured with the Rosenberg Self-Esteem scale [38] | 0.3 | 0.55 | 0.0125 | 0.992 (t test) | Mueser et al. [47] (2004), Howard et al. [18] (2010), Drake et al. [48] (1999). None of the studies shows difference in mean. σ is between 0.55 and 0.68. |
| Competitive employment or education during follow-up period | 50 % vs. 34 % | - | 0.0125 | 0.807 (chi-squared test) | Bond et al. [8] (2008) |
| Dichotomous yes/no |