Table 3.

AAQ item characteristics

Item		Monoto-nicity	GRM fit	GRM item parametersa
Item ID	Item description	Hi	S-X2 p-valueb	a	b1	b2	b3	b4	b5
AAQ_01	Ascending stairs	0.613	0.369	2.743	0.126	0.960	1.954	2.798	–
AAQ_02	Descending stairs	0.580	0.232	2.386	− 0.191	0.698	1.802	2.275	3.096
AAQ_03	Walking outside on a flat surface	0.628	0.030	2.857	0.130	1.168	1.443	2.193	3.259
AAQ_04	Walking outside on uneven terrain	0.634	0.667	2.964	0.156	1.079	1.429	2.444	–
AAQ_05	Walking inside: starting walking after at least 15 min sitting	0.629	0.069	2.467	− 0.526	0.879	2.173	3.363	–
AAQ_06	Ascending a bridge	0.657	0.499	3.453	0.087	1.326	2.123	2.928	–
AAQ_07	Descending a bridge	0.648	0.035	3.132	0.005	1.406	2.221	3.092	–
AAQ_08	Picking up an object from floor	0.584	0.030	2.260	0.092	1.033	1.710	2.869	–
AAQ_09	Rising from the floor	0.560	0.073	1.983	− 0.240	0.987	1.859	–	–
AAQ_10	Rising from a chair	0.630	0.284	2.693	− 0.346	1.230	2.024	3.526	–
AAQ_11	Sitting down on a chair	0.620	0.480	2.734	− 0.105	1.312	1.823	3.690	–
AAQ_12	Rising from a sofa	0.669	0.158	2.789	− 0.886	0.590	1.553	2.629	–
AAQ_13	Sitting down on a sofa	0.633	0.012	2.779	− 0.400	0.898	1.606	2.800	–
AAQ_14	Rising from a toilet	0.633	0.385	2.964	0.072	0.929	2.002	3.195	–
AAQ_15	Sitting down on a toilet	0.622	0.751	2.727	0.186	1.126	2.234	3.430	–
AAQ_16	Putting on shoes	0.499	0.654	1.403	− 1.561	− 0.259	1.433	3.055	–
AAQ_17	Taking off shoes	0.461	0.008	1.289	− 0.461	0.505	3.144	–	–

H_i Loevinger’s Homogeneity coefficient (on item level), GRM graded response model

^aIn GRMs, one slope and several (number of response options minus 1) threshold parameters are estimated for each item. While the slope parameter (a) specifies how strong an item is associated with the latent trait, threshold parameters (b_j) define the locations on the latent trait continuum at which an item responses are most informative

^bS-X² item fit statistics were evaluated after adjusting for multiple testing (p < 0.003)