Table 6

Dichotomous Rasch model analysis of psychological stress and mental effort endoscopic lumbar decompression.

Model Fit
Person ReliabilityMADaQ3aP
Scale0.7620.2740.01
Lumbar Endoscopic Psychological Stress and Mental Effort Item Statistics
CPT CodeMeasureInfitbOutfitc
63047−0.08271.0031.014
22102−0.20900.8670.617
63030−0.20900.8880.728
630050.29270.8270.594
63620−0.46441.1600.916
22869−0.72460.9730.704
226300.41720.8660.937
22612−0.08270.6890.375
225320.41721.1040.792
225330.66670.9190.542
226330.66670.9560.607
  • Abbreviation: CPT, Current Procedural Terminology.

  • a MADaQ3 = Mean of absolute values of centered Q_3 statistic with P value obtained by Holm adjustment.

  • b Infit = Information-weighted mean square based on the χ2 statistic with each observation weighted by its statistical information (model variance). This is more sensitive to unexpected patterns of observations by persons on items that are roughly targeted on them (and vice versa).

  • c Outfit = Outlier-sensitive means square statistic is more sensitive to unexpected observations by surgeons. Infit and outfit data between 0.6 and 1.4 indicate good fit of the Rasch model. Infit and outfit numbers outside this range suggest the presence of confounding factors, such as for CPT codes 63005, 22612, and 22533.