4.1 Error Handling

There are three layers of error checking:⁸

1. Required field checking—whether all required questions have been answered.
2. Type Validation—verify that questions contain valid data according to their declared type. Validation.
3. Assertions—arbitrary checks on data. Assertions.

Required fields fail serially—the system will notify the user of the required field, and direct him/her to it (usually through scrolling). A field is marked as fixed according to the rules in Managing Error State.