| Criteria | 1 (Poor) | 2 (Fair) | 3 (Good) | 4 (Very Good) | 5 (Excellent) | |-------------------------|-------------------------------------------------|-------------------------------------------------|-------------------------------------------------|--------------------------------------------------|-------------------------------------------------| | **Functionality** | Calculator is non-functional and unusable. | Basic functions work with frequent errors. | Functions correctly with occasional minor bugs. | All intended functions work with minor issues. | Flawless functionality with all features working perfectly. | | **User Interface** | UI is confusing and difficult to navigate. | UI functional but lacks intuitive design. | UI is clear and usable, but lacks sophistication. | UI is attractive and user-friendly. | UI is exceptionally designed, intuitive, and aesthetically pleasing. | | **Code Efficiency** | Code is inefficient and poorly structured. | Code works but is not optimized or clean. | Code is mostly well-structured and efficient. | Code is well-optimized and maintains good structure. | Code is exemplary in efficiency and structure, with excellent documentation. | | **Error Handling** | No error handling implemented. | Minimal error handling that often fails. | Adequate error handling for common issues. | Comprehensive error handling. | Robust error handling that gracefully manages all edge cases. | | **Accessibility** | Fails basic accessibility checks. | Meets only the minimal accessibility standards. | Good accessibility but misses some finer points. | Very good accessibility with minor gaps. | Excellent accessibility, fully compliant with WCAG 2.1 AA standards. | | **Testing & Debugging** | No testing or debugging performed. | Minimal testing that leaves significant bugs. | Some testing done, minor bugs remain. | Thorough testing and debugging, few issues remain. | Extensively tested and debugged, virtually bug-free. |