Table 10: SF-36 physical health scale Rasch analysis of standardised residual variance in Eigenvalue units for six waves of data collection.

Wave 1Wave 2 Wave 3
EigenvalueObservedExpectedEigenvalueObservedExpectedEigenvalueObservedExpected

Total raw variance in observations36.07100.00%100.00%36.07100.00%100.00%37.89100.00%100.00%

Raw variance explained by measures15.0741.80%42.50%15.0741.80%42.50%16.8944.60%45.70%

Raw variance explained by persons1.905.30%5.40%1.905.30%5.40%0.962.50%2.60%

Raw Variance explained by items13.1636.50%37.10%13.1636.50%37.10%15.9442.10%43.10%

Raw unexplained variance (total)21.0058.20%57.50%21.0058.20%57.50%21.0055.40%54.30%

Unexplained variance in 1st contrast8.0022.20%38.10%8.0022.20%38.10%7.7020.30%36.70%

Unexplained variance in 2nd contrast2.025.60%9.60%2.025.60%9.60%1.965.20%9.40%

Unexplained variance in 3rd contrast1.514.20%7.20%1.514.20%7.20%1.443.80%6.90%

Unexplained variance in 4th contrast1.313.60%6.20%1.313.60%6.20%1.233.20%5.80%

Unexplained variance in 5th contrast0.992.80%4.70%0.992.80%4.70%0.992.60%4.70%

Wave 4Wave 5Wave 6
EigenvalueObservedExpectedEigenvalueObservedExpectedEigenvalueObservedExpected

Total raw variance in observations37.07100.00%100.00%39.34100.00%100.00%41.08100.00%100.00%

Raw variance explained by measures17.0746.10%48.00%18.3446.60%48.60%20.0848.90%51.10%

Raw variance explained by persons2.456.60%6.90%2.426.10%6.40%2.686.50%6.80%

Raw Variance explained by items14.6239.40%41.10%15.9240.50%42.20%17.4042.30%44.20%

Raw unexplained variance (total)20.0053.90%52.00%21.0053.40%51.40%21.0051.10%48.90%

Unexplained variance in 1st contrast6.6417.90%33.20%7.5019.10%35.70%7.1417.40%34.00%

Unexplained variance in 2nd contrast2.105.70%10.50%2.065.20%9.80%2.245.50%10.70%

Unexplained variance in 3rd contrast1.544.20%7.70%1.584.00%7.50%1.563.80%7.40%

Unexplained variance in 4th contrast1.263.40%6.30%1.213.10%5.80%1.202.90%5.70%

Unexplained variance in 5th contrast1.072.90%5.30%1.032.60%4.90%1.042.50%4.90%

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