IRT Modeling Lab

1. Reverse Scoring

Items that are negatively worded in a scale must be rescored in a positive direction in order to match the other items in a scale. For example, if you have an item like
  • Are you disagreeable?
    Disagree Strongly   Disagree   Neither   Agree   Agree Strongly  
    in an agreeableness scale you will need to reverse score it.

    In the sample data provided, items a1, a5, a10, c1, c5, c7, and c10 are negatively worded and must be reverse scored before we can proceed. SPSS syntax is provided below which will recode the negatively worded items into positively scored items.

    SPSS Syntax:
      * Get raw data file (SPSS format already).
    GET
       FILE='C:\IRTtutorial\raw.SAV'.
    EXECUTE .

    *Reverese score.
    recode
    c1 a1 c5 a5 c7 a7 c10 a10
    (1=5) (2=4) (4=2) (5=1).
    Execute.

    *Save reversed scores to a different file.
    SAVE OUTFILE='C:\IRTtutorial\raw_reversed.SAV'.
    Execute.
         		 

    If you ran the syntax above SPSS would have created a new file raw_reversed.sav which has all the items scored in the same direction. You may download the file in order to compare your file with ours.
     
    Continue to next step
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