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Table 2 Sources of variation in health-related quality-of-life ratings estimated from a two-facet fully-crossed design, according to health state (n = 183)

From: Reliability of health-related quality-of-life assessments made by older adults and significant others for health states of increasing cognitive impairment

Source of variation Estimated variance component Percent of total variability
Current health state
 Person 0.205 34.3
 Rater 0.039 6.5
 Occasion 0.000a 0.0
 Person x Rater 0.100 16.8
 Person x Occasion 0.029 4.8
 Rater x Occasion 0.000a 0.0
 Residual 0.224 37.6
Mild to moderate stroke
 Person 0.133 20.4
 Rater 0.007 1.1
 Occasion 0.004 0.7
 Person x Rater 0.089 13.7
 Person x Occasion 0.001 0.2
 Rater x Occasion 0.000a 0.0
 Residual 0.418 64.0
Incurable brain cancer
 Person 0.067 16.4
 Rater 0.000a 0.0
 Occasion 0.000a 0.1
 Person x Rater 0.066 15.9
 Person x Occasion 0.000a 0.0
 Rater x Occasion 0.000a 0.1
 Residual 0.277 67.5
Severe dementia
 Person 0.025 11.1
 Rater 0.000a 0.0
 Occasion 0.000a 0.0
 Person x Rater 0.049 21.3
 Person x Occasion 0.000a 0.0
 Rater x Occasion 0.003 1.2
 Residual 0.152 66.5
  1. aNegative variances set to zero as recommended by Cronbach et al. [25]