Table 7.

Dichotomous Rasch model analysis work effort endoscopic lumbar decompression.

Model Fit
	Person Reliability	MADaQ3 a	P
Scale	0.764	0.324	<0.001

Endoscopic Lumbar RVU Work Effort Item Statistics
CPT Code	Measure	Infit b	Outfit c
63047	−0.383	0.985	0.649
22102	−0.652	1.203	0.874
63030	−0.118	0.920	0.680
63005	−0.652	0.941	0.652
63620	−0.652	1.277	1.889
22869	−0.789	0.848	0.650
22630	0.143	0.782	0.444
22612	−0.250	0.590	0.302
22532	0.533	0.906	0.953
22533	0.533	0.831	0.458
22633	0.143	0.770	0.412

Abbreviations: CPT, Current Procedural Terminology; RVU, relative value unit.

^aMADaQ3 = Mean of absolute values of centered Q_3 statistic with P value obtained by Holm adjustment.

^bInfit = Information-weighted mean square based on the χ ² 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).

^cOutfit = 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 22630, 22633, and 22612.