Don Riso developed nine "levels of development" for each Enneagram personality type. This is not only used to explain variations between people of the same type, but also to understand where an individual's level of health is within his or her type.
The levels are categorized as follows.
- Healthy - levels 1 through 3
- Average - levels 4 through 6
- Unhealthy - levels 7 through 9
Don Riso's levels of development describe how each Enneagram type can manifest in different ways depending on an individual's level of psychological health.
Basically, each individual will express a range of levels at any given time in their life. For example, an individual at one time in his or her life might express their type at levels 5 through 7, while at another time in life might express type at levels 3 through 5. The levels of development attempt to not only help explain why an individual's personality can express so differently throughout life but also why two people of the same personality type can seem so different.