When you first sign up for Formative, the default score threshold will reflect a traditional grading framework:

Silver/Gold users can change these default thresholds on the Profile Settings page by clicking "My Account" on the left side menu and selecting "Settings."

From there, you have the ability to adjust score thresholds in the following ways:

Once you have changed your thresholds and clicked "Save," these changes will also take affect for your students. Any formatives that are graded and returned will conform to the thresholds and color-coding you have set up in your account.

Students see the same color coding for score thresholds in their progress bar as their teacher when scores are returned within a formative.

Learn how to set default Assign settings! (Silver/Gold Feature)
How to set default standards