Table 3

Prewebinar survey DIF detection procedure for ordinal data based on adjacent category logit model.

Survey Item	Statistic	P	Adjusted P
Articulating instruments	0.5462	0.460	0.723
Multiportal technique	0.0236	0.878	0.878
PELIF	0.8548	0.355	0.723
Facet cyst	0.8608	0.354	0.723
Low-grade spondylolisthesis	0.6184	0.432	0.723
Transforaminal posterolateral HNP	0.9112	0.340	0.723
Transforaminal central HNP	1.6761	0.195	0.723
Transforaminal lateral stenosis	0.3394	0.560	0.770
Transforaminal central stenosis	0.0741	0.785	0.878
Transforaminal facet cyst treatment	0.0458	0.831	0.878
Transforaminal migrated HNP	1.0136	0.314	0.723

Abbreviations: DIF, differential item functioning; HNP, herniated nucleus pulposus; PELIF, percutaneous endoscopic lumbar interbody fusion.
Note. DIF likelihood ratio statistics are estimated by using difNLR and difORD functions. Adjusted P values calculated by the likelihood ratio test using multiple comparisons.