Harman’s one-factor test for common method bias

The sole aim of this tutorial is to teach you how to assess common method bias using Harman’s one-factor test for your study especially when the same measurement instrument is used to collect data for both dependent and independent variables.

How to do this in SPSS?

  1. In SPSS, click Analyze → Dimension Reduction → Factor, you will be presented with the dialogue box below.
  1. Move all the items measuring the constructs to the variables: box
  2. Click on Extraction, select Fixed number of factors and input 1 (see the figure below for more details)
  1. Click Continue and then OK to view the output.

We are interested in the table below.


If the total variance extracted by one factor exceeds 50%, common method bias is present in your study. There is no problem with common method bias in this data since the total variance extracted by one factor is 30.418% and it is less than the recommended threshold of 50%.

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