Questionnaire Development: SPSS and ReliabilityPersonality LabOctober 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

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

Running Reliability Analysis

Output from Reliability Analysis

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