Comprehensive context and supporting research with primary survey and secondary sources clearly justifies the problem description and design opportunity.

Specification table fully justifies requirements with measurements and research outcomes (e.g., heat absorption, water-loss calculations).

Design brief lacks full quantification of performance parameters (cost limits, exact footprint) and methodology details for the survey.

Some placeholders in the specification (e.g., size values) indicate incomplete linkage between research and final parameters.

Developed multiple feasible ideas that meet specifications and explore solutions, with varied hanging, folding and lid options.

Concept modelling (card and plywood mock-ups, load tests) is used effectively and informs design refinements.

Selection of the chosen concept is thoroughly justified against size, stability, water volume and usability requirements.

Quantitative analysis of some models (hinge torque, tilt angle) is missing, reducing analytical rigor.

Justification omits cost-benefit and material trade-off discussion, limiting the robustness of the final selection.

Comprehensive material and manufacturing choices with weighted scoring matrices and evidence-based component selection.

Accurate and detailed orthographic drawings, exploded CAD views, BOM and assembly diagrams enable third-party manufacture.

Manufacturing plan outlines processes, equipment, QC checks and risk assessments in detail.

Lifecycle and sustainability impacts are not addressed, limiting the depth of material justification.

3D-print parameters (layer height, infill percentage) are unspecified, reducing fidelity of the manufacturing plan.

Proposed iterative improvements demonstrate holistic thinking (lid coverage, handles, hook durability).

Testing includes a range of methods (photos, angle measurement, user survey) providing some evidence of prototype evaluation.

Testing strategy lacks precise pass/fail thresholds and long-term measurement criteria.

Prototype evaluation is only partially quantitative and missing statistical summaries of user feedback.

Improvement recommendations are not fully assessed for cost or manufacturability impact.