Table 1.

English, Spanish and Brazilian versions of published studies using dimensional assessment and other methods to reduce the number of items of IQCODE

Item		Study based on a dimensional structure (factorial) analysis
		No		Yes
		Morales et al.,1995 [27]	Perroco et al.,2009 [28]	Jorm, 1994 [7]	Fuh et al., 1995 [10]	Tang et al., 2004 [13]
		(Corr, ROC)a	(ROC)	(PCA)	(PCA, DA)	(RA)
1.	Recognizing the faces of family and friends	Xb	X	X	X
2.	Remembering the names of family and friends			X
3.	Remembering things about family and friends	X
4.	Remembering things that have happened recently
5.	Recalling conversations a few days later
6.	Forgetting what he/she wanted to say in the middle of a conversation			X
7.	Remembering his/her address and telephone number	X	X
8.	Remembering what day and month it is
9.	Remembering where things are usually kept
10.	Remembering where to find things which have been put in a different place from usual
11.	Adjusting to any change in his/her day-to-day routine	X	X	X
12.	Knowing how to work familiar machines around the house	X	X		X
13.	Learning to use a new gadget or machine around the house					X
14.	Learning new things in general					X
15	Remembering things that happened to him/her when he/she was young		X	X	X
16	Remembering things he/she learned when he/she was young	X	X	X
17	Understanding the meaning of unusual words		X	X	X	X
18	Understanding magazine or newspaper articles		X	X	X	X
19	Following a story in a book or on TV		X		X
20	Composing a letter to friends or for business purposes	X	X	X	X	X
21	Knowing about important historical events of the past	X	X	X
22	Making decisions on everyday matters				X
23	Handling money for shopping
24	Handling financial matters, e.g. the pension, dealing with the bank	X
25	Handling other everyday arithmetic problems
26.	Using his/her intelligence to understand what's going on and to reason things through				X

^aIn brackets, statistical methods used in the studies — Corr: items correlations with total score; ROC: Receiver Operating Characteristic curve; PCA: principal component analysis; DA: stepwise discriminant analysis, followed by jack-knife procedure of resampling; RA: Rasch analysis/Item Response Theory modelling

^b Removed items