What are the differences between success factors and success criteria?

They are quite different, project success criteria are the criteria that, if accomplished, the project will be considered a success. The project success criteria are usually defined by the project sponsor (and other stakeholders).

Examples of project success criteria:

- Finishing the project on time
- Finishing the project on budget
- Quality of the product meeting the specifications

Project success factors are those factors that CAN lead to project success. Examples of project success factors are:

- A proactive project manager / a proactive project sponsor
- A coherent and experienced team
- Employing the right project management methodology
- Formal handling of change requests
- A flexible client