Table 4: SF-36 total scale Rasch analysis of standardised residual variance in Eigenvalue units for six waves of data collection.

Wave 1Wave 2Wave 3
EigenvalueObservedExpectedEigenvalueObservedExpectedEigenvalueObservedExpected

Total raw variance in observations86.71100.00%100.00%92.22100.00%100.00%92.42100.00%100.00%
Raw variance explained by measures50.7158.50%58.70%56.2261.00%61.10%56.4261.00%61.30%
Raw variance explained by persons3.474.00%4.00%1.932.10%2.10%2.042.20%2.20%
Raw Variance explained by items47.2454.50%54.70%54.3058.90%59.00%54.3858.80%59.10%
Raw unexplained variance (total)36.0041.50%41.30%36.0039.00%38.90%36.0039.00%38.70%
Unexplained variance in 1st contrast12.6014.50%35.00%12.5713.60%34.90%12.2613.30%34.10%
Unexplained variance in 2nd contrast3.023.50%8.40%3.053.30%8.50%3.033.30%8.40%
Unexplained variance in 3rd contrast1.892.20%5.20%1.781.90%4.90%1.842.00%5.10%
Unexplained variance in 4th contrast1.591.80%4.40%1.541.70%4.30%1.501.60%4.20%
Unexplained variance in 5th contrast1.241.40%3.40%1.271.40%3.50%1.261.40%3.50%

Wave 4Wave 5Wave 6
EigenvalueObservedExpectedEigenvalueObservedExpectedEigenvalueObservedExpected

Total raw variance in observations92.10100.00%100.00%91.96100.00%100.00%94.92100.00%100.00%
Raw variance explained by measures56.1060.90%61.50%55.9660.90%61.70%58.9262.10%63.00%
Raw variance explained by persons3.593.90%3.90%4.054.40%4.50%4.574.80%4.90%
Raw Variance explained by items52.5157.00%57.60%51.9156.40%57.20%54.3557.30%58.10%
Raw unexplained variance (total)36.0039.10%38.50%36.0039.10%38.30%36.0037.90%37.00%
Unexplained variance in 1st contrast12.4113.50%34.50%12.0813.10%33.60%11.3311.90%31.50%
Unexplained variance in 2nd contrast3.063.30%8.50%3.203.50%8.90%3.223.40%8.90%
Unexplained variance in 3rd contrast1.882.00%5.20%1.952.10%5.40%2.172.30%6.00%
Unexplained variance in 4th contrast1.501.60%4.20%1.531.70%4.30%1.551.60%4.30%
Unexplained variance in 5th contrast1.271.40%3.50%1.251.40%3.50%1.301.40%3.60%

Notes. > 60% unexplained variance in the Rasch factor; Eigenvalue in the first contrast <3.0; < 10% unexplained variance in the first contrast.