Comparisons of measures at two time-points or in two situations can become complicated. Example 12 illustrates a straightforward situation. It uses the 13 motor items of the FIM®. This example uses the 18 items of the FIM, 13 motor and 5 cognitive, at two time points. There is a 7-level rating scale that is intended to operate in the same way across all items.

 

In exam17s.txt, the data have been stacked. The items are modeled to maintain their difficulties across the two time points, and the 52 patients are entered twice, once at admission to rehabilitation and once at discharge from it, so there 104 data records. Changes in patient independence can be identified by cross-plotting the admission and discharge measures for each patient, as in Example 12. This can be done by using the Plots menu to plot the measures against themselves, and then, in EXCEL, pasting the discharge measures over the top of the admission measures for the y-axis.

 

In exam17r.txt, the data have been racked. The persons are modeled to maintain their abilities across the two time points, and the 18 FIM items are entered twice, once at admission to rehabilitation and once at discharge from it, so there 36 items. Average changes in patient performance on individual items can be identified by cross-plotting the admission and discharge measures for each item. This can be done by using the Plots menu to plot the measures against themselves, and then, in EXCEL, pasting the discharge measures over the top of the admission measures for the y-axis.

 

A further feature is the contrasts in the Principal Components Analysis of Residuals, Tables 23 and 24. The 13 motor items and 5 cognitive items are probing different aspects of patient independence. Do they function as one variable in this sample? See Principal components/contrast. Patients also have different impairments. Are their measures comparable? See Differential Item Function.

 

; This control file is EXAM17S.TXT

TITLE='Example 17S: 18-item FIM control file: stacked admission then discharge'

ITEM1=1  ; Responses start in column 7

NI=18  ; 13 motor items + 5 cognitive items

NAME1=20 ; start of person label

; variables in person label

@SETTING=$S1W1 ; setting: A=Admission, D=Discharge

@SEX=$S3W1 ; Gender: 1=Male, 2=Female

@IGC=$S5W2 ; Impairment Group Code: 8=Orthopedic, 9=Cardiac, 10=Pulmonary, 11=Burns, 12=Congenital, 13=Other

@ID=$S8W2 ; Patient sequence number

 

; variables in item label

@SUBTEST=$S1W1  ; subtest: M=Motor, C=Cognitive

@ILETTER=$S3W1 ; code letter of item

 

CODES=1234567 ; 7 level rating scale

CLFILE=* ; Defines the rating scale

1 0% Independent

2 25% Independent

3 50% Independent

4 75% Independent

5 Supervision

6 Device

7 Independent

*

&END

M A. EATING

....

C R. MEMORY

END NAMES

334412312331123112 A 1  8  1

432322442223134444 A 2  8  2

....

 

; This control file is EXAM17R.TXT

TITLE='Example 17: 18-item FIM control file: racked admission and discharge'

ITEM1=1  ; Responses start in column 7

NI=37  ; 13 motor items + 5 cognitive items: admission and discharge

NAME1=39 ; start of person label

 

; variables in person label

@SEX=$S1W1 ; Gender: 1=Male, 2=Female

@IGC=$S3W2 ; Impairment Group Code: 8=Orthopedic, 9=Cardiac, 10=Pulmonary, 11=Burns, 12=Congenital, 13=Other

@ID=$S5W2 ; Patient sequ. number

 

; variable in item label

@SETTING=$S1W1 ; setting: A=Admission, D=Discharge

@SUBTEST=$S3W1  ; subtest: M=Motor, C=Cognitive

@ILETTER=$S5W1 ; code letter of item

 

CODES=1234567 ; 7 level rating scale

CLFILE=* ; Defines the rating scale

1 0% Independent

2 25% Independent

3 50% Independent

4 75% Independent

5 Supervision

6 Device

7 Independent

*

&END

A M A. EATING

....

A C R. MEMORY

-      Blank for ease of seeing

D M A. EATING

....

D C R. MEMORY

END NAMES

334412312331123112 554535546665345545 1  8  1

432322442223134444 777677777666567777 2  8  2

....