Cronbach's Alpha Reliability
These instructions assume you have entered your data into the SPSS spreadsheet.

  1. Move the cursor to the Statistics option on the menu bar at the top of the screen. Click on the word Statistics.
  2. On the menu under Statistics, click on the word Scale.
  3. On the side menu, click on Reliability Analysis....
  4. The purpose of a reliability analysis is to determine how consistently the selected variables measure some construct. For example, you might believe that Var0001, Var0005, and Var0009 all measure the same construct and you could combine a subject's response to those variables.
  5. You need to inform the program of which variables you are considering combining. Each of your variables will be listed in the box on the left side of the screen. In this example, Var0001 is one of the variable you wish to include. You would click on Var0001 to select it. The name should be highlighted. You would click on the > to move the variable name into the Items: box.
  6. You would continue step 5 for each of the variables you wish to use. In this example, you would repeat step 5 for Var0005 and Var0009.
  7. Move the cursor to the Statistics... button and press the mouse button once.
  8. Because you would like to have the means for your variables printed, you click on the box in front of Means in the Summaries section.
  9. It is also useful to see how each variables influences the reliability. For this reason you click on the box in front of the Scale if item deleted in the Descriptives for section.
  10. Click on the Continue button.
  11. Click on the OK button to run Cronbach's Alpha reliability.

Del Siegle, Ph.D.
Neag School of Education - University of Connecticut