1 🔍 Add Qualitative Interviewsv

| Why Do It? | Lightweight Depth |

|------------|------------------|

| • Captures felt cognitive alignment & usability nuances that numbers miss. <br>• Reviewer buzz-word: “mixed-methods validity.” | • Semi-structured 15-min Zoom calls with 40 participants (10 % sample). <br>• Thematic coding in NVivo; inter-rater κ > 0.75. <br>• Cost ≈ $3 000 incentives + 40 hrs RA time. |

Minimal insertion to manuscript: 1 figure (word cloud or theme map), 300-word subsection.

2 🔁 Cross-Validation with Mathematical-Modeling Experts

| Why Do It? | Minimal Path |

|------------|-------------|

| • Establishes content validity of set-theory tasks & CSSO hints. <br>• Anticipates reviewer concern: “Are questions pedagogically sound?” | • Recruit 6 subject-matter experts (SMEs). <br>• Delphi-style two-round rating of (a) problem difficulty, (b) cognitive fit of CSSO recommendations. <br>• Report ICC for consensus (target > 0.8). <br>• Cost ≈ $1 200 honoraria. |

Insert into Methods → “Task Validation.” Adds credibility, low overhead.

3 📱 Mobile Version for Accessibility

| Benefit | Lift Required |

|---------|---------------|

| • Broader demographic reach, potential follow-up study on anytime/anywhere learning. <br>• Good for “impact” paragraph in journal cover letter. | • Wrap existing web app in React Native / Flutter WebView. <br>• Ensure eye-tracking alt (front-camera gaze proxy). <br>• QA on iOS/Android tablets. <br>• Dev time ~4 weeks, $8-10 k. |

May delay timeline; consider as Phase 1b pilot with small subset (n = 60) to avoid derailing Q3 schedule.

Quick Decision Matrix

| Option | Effort | Reviewer Value | Time Risk | Recommend? |