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Table 4 The estimated variance components and percentage of variance accounted for by effects (percent) for p × i design in G-study for four domains of quality of life instrument QLICD-PU (\({\text{n}}_{{\text{p}}}^{{\prime }} = 153\))

From: Development and validation of the peptic ulcer scale under the system of quality of life instruments for chronic diseases based on classical test theory and generalizability theory

Domain p(person) i(item) p* i(person*item)
Variance component Percent (%) Variance component Percent (%) Variance component Percent (%)
PHD (\({\text{n}}_{{\text{i}}}^{{\prime }} = 8\)) 0.517 27.80 0.224 12.04 1.119 60.16
PSD (\({\text{n}}_{{\text{i}}}^{{\prime }} = 11\)) 0.547 35.92 0.128 8.40 0.848 55.68
SOD (\({\text{n}}_{{\text{i}}}^{{\prime }} = 11\)) 0.190 12.20 0.092 5.91 1.275 81.89
SPD (\({\text{n}}_{{\text{i}}}^{{\prime }} = 14\)) 0.143 8.99 0.257 16.15 1.191 74.86
  1. PHD: physical domain, PSD: psychological domain, SOD: social domain, SPD: specific domain,
  2. p: person effect, i: item effect, p × i: person-by-item interaction effect