Table 2.

Estimated difficulty and discrimination parameters from the 2PL‐model.

Item	Difficulty parameter value	P (x=1 | z=0)	Discrimination parameter value	95% confidence interval	DIF due to
S2PD II left	−1.076	.893	1.97	1.46 – 2.34	Neuropathy complaints
S2PD II right	−1.040	.916	2.30	1.74 – 2.86	Type of diabetes
S2PD I left	−0.984	.867	2.57	1.93 – 3.21
S2PD III left	−0.929	.837	1.76	1.35 – 2.17
S2PD IV right	−0.915	.881	2.18	1.68 – 2.69
S2PD V left	−0.901	.897	2.40	1.85 – 2.96
S2PD V right	−0.877	.943	3.21	2.42 – 4.00
S2PD I right	−0.862	.900	2.55	1.97 – 3.13
S2PD IV left	−0.844	.894	2.53	1.96 – 3.10
S2PD III right	−0.839	.859	2.16	1.66 – 2.65
M2PD II left	−0.657	.760	1.76	1.35 – 2.16	Gender, Tinel
M2PD III left	−0.618	.757	1.84	1.42 – 2.26	Gender, type of diabetes, age
M2PD III right	−0.580	.758	1.97	1.53 – 2.40	Gender
M2PD II right	−0.416	.711	2.16	1.69 – 2.64
M2PD IV left	−0.392	.665	1.75	1.36 – 2.15	Tinel
M2PD IV right	−0.368	.683	2.09	1.62 – 2.56	Duration of diabetes
M2PD I left	−0.279	.673	2.59	2.01 – 3.17	Gender, type of diabetes, age, neuropathy complaints
M2PD I right	−0.260	.648	2.34	1.81 – 2.87
Vibration sense IP lefta	0.250	.429	1.14	0.86 – 1.42	Gender, age
Vibration sense IP righta	0.250	.429	1.14	0.86 – 1.42	Gender, age
Vibration sense MM righta	0.498	.384	0.95	0.70 – 1.20	Age
Vibration sense MM lefta	0.601	.346	1.06	0.79 – 1.33	Age
S1PD I left	0.781	.094	2.90	2.17 – 3.64
S1PD I right	0.835	.117	2.43	1.83 – 3.02	Neuropathy complaints
S1PD V left	0.958	.079	2.57	1.93 – 3.21	Neuropathy complaints, Tinel
Numbnessa	0.960	.234	1.24	0.93 – 1.54	Type of diabetes, neuropathy complaints, Tinel
S1PD V right	0.966	.070	2.67	1.99 – 3.36	Age, neuropathy complaints
S1PD II right	1.012	.145	1.75	1.33 – 2.18
S1PD II left	1.018	.144	1.75	1.33 – 2.17
S1PD III left	1.371	.012	3.23	2.33 – 4.13	Type of diabetes, neuropathy complaints
S1PD III right	1.405	.022	2.71	1.98 – 3.43
S1PD IV left	1.532	.022	2.46	1.80 – 3.13
S1PD IV right	1.578	.026	2.29	1.68 – 2.90	Neuropathy complaints
Prior ulcer	1.696	.057	1.65	1.23 – 2.08	Neuropathy complaints
Cold stimulus lefta	1.812	.097	1.23	0.89 – 1.57	Gender
Cold stimulus righta	1.902	.091	1.21	0.88 – 1.54	Duration of diabetes
Romberg testa	2.157	.143	0.83	0.56 – 1.10	Gender, type of diabetes, age
Amputation lefta	3.159	.001	2.16	0.79 – 3.53
Amputation righta	3.322	.004	1.64	0.79 – 2.49

*Roman capitals are indicatives of test locations: I, hallux; II, medial heel; III, first dorsal web; IV, lateral foot; V, fifth toe. IP, interphalangeal joint; MM, medial malleolus. For details on statistical information on DIF, see Supplementary Table SB.

^a Items included based on discrimination parameter value 1.