Questionnaire Development Part II: SPSS, Reliability, and ValidityPersonality LabOctober 11, 2010

Tasks for Analyzing Friend/Family Data•Several tasks are identical to those

completed in the computer lab. For these, I’ll simply state them in order to refresh your memory. For additional review, click on the link to see Friday’s slides called Questionnaire Development: SPSS and Reliability or go to our website.

Initial Tasks to Analyze Friend/Family Data – Google Docs and Excel• Open Google Docs Spreadsheet• Download Spreadsheet to Desktop in

Excel Format• Open Spreadsheet in Excel and Change

Column Headings from Questionnaire Items to Short Variable Names: TIP – Name your questionnaire items Q1-Q10 and name the items for the validity questionnaire V1-V10 (or V12, for example, if there are 12 items)

• Save your excel file

Initial Tasks to Analyze Friend/Family Data -- SPSS•Open SPSS•Click cancel on opening screen•File > Open > Data – to open your Excel

spreadsheet in SPSS (remember the file type is .xls and it is on your desktop)

•After your data opens up in SPSS, save it in case you have problems later on (File > Save as >file name)

Initial Tasks to Analyze Friend/Family Data – Reverse Code Items•In SPSS click Transform > Recode into

same variables•Select items to reverse code•Click on “Old and New Values”•TIP – remember to reverse code your

questionnaire items and questions from the “validity questionnaire.” If all are on same response scale (e.g., 1-4), do all at the same time. If different scales (e.g., 1-4 & 1-5), do separately

Run Reliability Analysis on Your Questionnaire• Analyze > Scale > Reliability Analysis• Select items for analysis• Click “Statistics” and check “item” and

“scale if item deleted”• Click continue• Click OK, See Output• TIP – Run once on your questionnaire items.

We’re not revising, this is the finished product, so we run once to determine final reliability of your questionnaire. No need to run on validity questionnaire

Beginning of New Tasks

•To finish your analysis, we need to do two tasks that will be new to you

•First, we need to calculate the overall score for your questionnaire and the validity questionnaire.

•Second, we need to correlate your two questionnaires.

•On to the first task

Total Up Scores for Each Questionnaire•My example has 3 variables for my

questionnaire and 3 variables for the validity questionnaire

•We want to add up Q1, Q2, and Q3. Then add V1, V2, and V3

Total Up Scores for Each Questionnaire, cont.•Go to Transform > Compute Variable•I added up Q1, Q2 and Q3 and the total is

called MyHappy (you can name it anything you want)

Total Up Scores for Each Questionnaire, cont.•Click OK, SPSS calculates MyHappy•Return to the SPSS Data and MyHappy

shows up

Total Up Score for Validity Q•Go to Transform > Compute Variable•I added up V1, V2 and V3 and the total is

called ValidHappy (again, call it whatever you like)

Total Up Score for Validity Q, cont.•Click OK, SPSS calculates ValidHappy•Return to the SPSS Data and ValidHappy

shows up•We now have scores for our two

questionnaires•Now for the last task

Correlate Your Questionnaire with Validity Questionnaire

•I want to correlate MyHappy with ValidHappy

•Go to Analyze > Correlate > Bivariate

Output from Correlation Analysis•Click OK, analysis runs, see output•Correlation between MyHappy and

ValidHappy is r=.903 (that’s big). I made up the data. Your correlation will probably be smaller

Your Analyses are Complete!!

•You should now have everything needed to finish writing your questionnaire assignment.

•Pay close attention to the Instructions on the Assignment sheet.

•Good Luck!