问题
I'm using Cronbach's alpha to analyze data in order to build/refine a scale. This is a tedious process in SPSS, since it doesn't automatically optimize the scale, so I'm hoping there is a way to use syntax to speed it up.
So I start with a set of items, set up the OMS control panel to capture the item-total statistics table, and the run the alpha analysis. This pushes the item-total stats into a new dataset. Then I check the alpha value, and use it in syntax to screen out items that have a greater alpha-if-deleted value.
Then I re-run the analysis with only the items passed the screening. And I repeat, until all the items pass the screening. Here is the syntax:
* First syntax sets up OMS, and then runs the alpha analysis.
* In the reliability syntax, I have to manually add the variables and the Scale name.
* OMS.
DATASET DECLARE alpha_worksheet.
OMS
/SELECT TABLES
/IF COMMANDS=['Reliability'] SUBTYPES=['Item Total Statistics']
/DESTINATION FORMAT=SAV NUMBERED=TableNumber_
OUTFILE='alpha_worksheet' VIEWER=YES.
RELIABILITY
/VARIABLES=
points_18618
points_18618
points_3286
points_3290
points_3583
points_4018
points_7775
points_7789
points_7792
points_18631
points_18652
/SCALE('2017 Fall CRN 4157 Exam 01 v. 1.0') ALL
/MODEL=ALPHA
/SUMMARY=TOTAL.
* Second syntax identifies any variables in the OMS dataset that are LTE the alpha value.
* I have to manually enter the alpha value...
DATASET ACTIVATE alpha_worksheet.
IF (CronbachsAlphaifItemDeleted <= .694) Keep =1.
EXECUTE.
SORT CASES BY Keep(D).
Ideally, instead of having to repeat this process over and over, I'd like syntax that would automate this process.
Hope that makes sense, and if you have a solution thanks in advance (this has been bugging me for years!) Cheers
来源：https://stackoverflow.com/questions/48846780/scale-building-in-spss