What makes an IB SEHS IA idea “high scoring”?

A high-scoring IB SEHS investigation usually feels boring in the best way: one clear variable, one clear measurement, and a method you can repeat without chaos. Examiners reward research design that anticipates confounders and actively manages them. They also reward analysis that matches the question you asked, not analysis you used because it looks impressive. Your conclusion should be proportional to your data, meaning you avoid overclaiming from small samples. Finally, your evaluation is where top IAs separate themselves, because you admit limitations and propose realistic improvements.

How much data do I need for an IB SEHS IA?

You need enough data to show patterns and variability, not just a single dramatic result. In IB SEHS, that usually means repeated trials per condition and a sample size that is large enough to calculate meaningful descriptive statistics. More important than chasing a perfect number is making your data collection consistent and well-controlled. A smaller sample with clean controls can outperform a bigger sample with messy protocols. Also, plan your data table before you collect anything so you do not discover missing units and incomplete trials later. If you are unsure, run a pilot and adjust before your full collection.

Can I use classmates as participants?

Yes, classmates are commonly used in IB SEHS, but your write-up should treat them like real participants, not convenient bodies. That means informed consent, clear instructions, and the right to withdraw without pressure. You should avoid risky protocols, extreme fatigue, unsafe stimulants, or anything that could be considered coercive. Explain how you protected privacy (codes instead of names) and how you kept the environment safe. If you are comparing groups (trained vs untrained, male vs female), acknowledge sampling bias and avoid stereotypes in interpretation. Ethical clarity strengthens your evaluation and makes the whole report more credible.