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Questionnaire Development: SPSS and Reliability. Personality Lab October 8, 2010. Open Google Docs Spreadsheet. Download Spreadsheet to Desktop in Excel Format. Save to Desktop. Get Data Ready for Analysis: Open in Excel. Verify responses are numbers Column headings are questions-- revise.
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Questionnaire Development: SPSS and Reliability Personality Lab October 8, 2010
Get Data Ready for Analysis: Open in Excel • Verify responses are numbers • Column headings are questions-- revise
Getting Data into SPSS • Open SPSS • Click “cancel” on opening screen
Getting Data into SPSS • File > Open > Data
Getting Data into SPSS • Change “files of type” to Excel
Getting Data into SPSS • Open your spreadsheet, Click “OK”
Getting Data into SPSS • Spreadsheet Opens
Save SPSS File • Save as type – make sure it is “.sav”
Reverse Coding Items • Transform > Recode into same variables • Select items to reverse code • Click on “Old and New Values”
Reverse Coding Items • If 4 point scale • Old value enter 4, new value enter 1, click “add” • Old value enter 3, new value enter 2, click “add” • When finished click continue to reverse other items • Click OK when all items reverse coded
Running Reliability Analysis • Analyze > Scale > Reliability Analysis • Select items for analysis • Click “Statistics” and check “item” and “scale if item deleted” • Click continue • Click OK • See Output
Interpret Output • Case Processing Summary – N is # of Test Takers • Reliability Statistics – Cronbach’s Alpha is our stat, .50-.60 marginal, .61-.70 good, .71-85 very good • Item Statistics – average response for all test takers • Item total Statistics – use to determine which items stay, get dropped
Item Total Statistics • If reliability goes up after deleting item, bad item • If reliability goes down after deleting item, good item • See item total correlations • Q3 good item, Q2 bad item
Revise Questionnaire • Use best judgment to exclude items • Drop a couple of items, rerun reliability analysis, check results • Drop more items, check results, Cronbach’s Alpha go up or down? • Pick final set of items • Run Reliability Analysis with final set of items • If good reliability, use questions for your questionnaire
Update Questionnaire • Include subset of old questionnaire items • Include validity questionnaire items • Check for typos • Submit to friends and family