Table 3. Efficacy outcomes: analyses of covariance
ANCOVAa for t1 scoreANCOVAa for t2 score
n Regression co-efficient Partial eta squared b n Regression co-efficient Partial eta squared
( 95% CI ) ( 95% CI ) c ( 95% CI ) ( 95% CI ) b
DCSPDA23-3.5 (-12.6 to 5.6)0.014 (0.000 to 0.143)
No PDA23
EPDSPDA231.4 (-1.6 to 4.5)0.020 (0.000 to 0.158)21-1.3 (-4.1 to 1.5)0.021 (0.000 to 0.163)
No PDA2323
STAI (state)PDA235.1 (1.0 to 11.3)0.062 (0.000 to 0.230)20-3.8 (-11.4 to 3.8)0.025 (0.000 to 0.174)
No PDA2323
Knowledge questionnairePDA230.13 (-0.86 to 1.1)0.002 (0.000 to 0.090)
No PDA23
  • aANCOVA model of effect of allocation, adjusted for baseline score of the relevant outcome measure. bStandardised effect sizes were estimated using partial eta squared (by convention, values of 0.01, 0.09, and 0.25 indicate small, medium, and large effect sizes respectively). cThe lower limit of the confidence interval was estimated as 0.0 for all analyses.

  • ANCOVA = analysis of covariance. CI = confidence intervals. DCS = decisional conflict scale. EPDS = Edinburgh postnatal depression scale. PDA = patient decision aid. STAI = state-trait anxiety inventory.