Understanding Standard Deviations in TTI SI Reports

Understanding where the mean and how your respondent aligns with it will help you bring out more depth to the report.

In the simplest term, the mean is the average of a set of data.  It is the exact middle of the range of data collected.Mean

When talking about the mean and how a person aligns with it, the other term we often use is standard deviation.  As the diagram above shows, the following labels coincide with one or more standard deviations:

Mainstream – the person’s score fell within one standard deviation from the mean. That is one standard deviation above the mean and one standard deviation below the mean. People who fall in the first standard deviation above or below the mean on a driving forces assessment will share a similar level of motivation with about 68% of the population.

Passionate – the person’s score fell within the second standard deviation above the mean. Only 13% of people will be as passionate about that driving force.

Indifferent – the person’s score fell within the second standard deviation below the mean. Only 13% of people will share the indifference toward or even avoidance of that driving force.


Extreme – the person’s score fell within the third standard deviation below or above the mean. Only 2% of people share a similar level of motivation either above or below the mean respectively.

When you see these terms, you can now speak to them with more confidence.

If you have any questions, or if something does not work, please reach out to our Partner Support Team member by clicking the chat button in the lower right corner, or call us at (800) 869-6908.  We will be happy to help.