Table 1.

Mokken scale (item response theory) analyses for the development of the Community Screening Instrument for Dementia (CSI-D) brief informant and cognitive scales

	n	Item difficulty	Observed Guttman errors	Expected Guttman errors	Loevinger H coefficient	z-statistic	p-value
Cognitive scale
Describing the use of a hammer	15 022	0.024	486	2289.2	0.79	73.2	<0.00001
Naming elbow	15 022	0.032	1105	2933.0	0.62	64.7	<0.00001
Pointing to window and then to door	15 022	0.040	1264	3457.8	0.63	69.9	<0.00001
Locating nearest store	15 022	0.059	1679	4423.4	0.62	73.1	<0.00001
Orientation to season	15 022	0.062	1793	4523.7	0.60	71.3	<0.00001
Orientation to day of the week	15 022	0.100	2210	5328.3	0.59	66.2	<0.00001
Delayed recall of three words	15 022	0.283	2597	7570.0	0.66	62.1	<0.00001
Whole Scale	15 022	-	5567	15262.7	0.64	116.3	<0.00001
Informant scale
Often forgets where she/ he had put things	14 922	0.523	2334	7039.5	0.67	90.4	<0.00001
General decline in mental functioning	14 922	0.868	1833	5459.0	0.66	101.4	<0.00001
Change in ability to think and reason	14 922	0.908	1638	5297.7	0.69	117.2	<0.00001
Sometimes forgets what happened the day before	14 922	0.913	2143	7117.2	0.70	124.7	<0.00001
Sometimes forgets where she/ he is	14 922	0.968	1201	4291.7	0.72	108.3	<0.00001
Difficulty dressing	14 922	0.982	1105	3605.7	0.69	81.2	<0.00001
Whole scale	14 922	-	5127	16405.4	0.69	174.9	<0.00001