# 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?

- In SPSS, click Analyze → Dimension Reduction → Factor, you will be presented with the dialogue box below.

- Move all the items measuring the constructs to the
**variables:**box - Click on
**Extraction**, select**Fixed number of factors**and input**1**(see the figure below for more details)

- Click
**Continue**and then**OK**to view the output.

We are interested in the table below.

## Interpretation

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%.