MYP Chemistry: Processing Results (Criterion C) FAQ

Criterion C — Processing and evaluating — asks you to present your data clearly, interpret it using chemistry reasoning, judge whether your hypothesis held up, evaluate your method's validity, and suggest realistic improvements. It's marked out of 8 across five strands, and it's where most students lose marks by describing data instead of genuinely analysing it.

Criterion C is one of four MYP Sciences criteria — alongside Knowing and understanding, Inquiring and designing, and Reflecting on the impacts of science. It covers everything you do with your data once it's collected: presenting it, interpreting it, and evaluating both your hypothesis and your method against what actually happened in the lab.

Criterion B (Inquiring and designing) is marked before you run the experiment — your research question, hypothesis, variables and method. Criterion C (Processing and evaluating) is marked afterwards, using the data you actually collected. Confuse the two and you end up re-describing your method in Criterion C instead of analysing results — a mistake I see constantly in Year 10 lab reports.

Start by transforming raw data into a processed form — averages, rates, concentrations — in a labelled table with correct units and consistent significant figures. Then describe the trend using real figures from your data, not vague language, and finish by linking that trend back to the chemistry you'd expect using precise terms.

Take the uncertainty of your measuring equipment — usually half its smallest division — and carry it through your calculations. For a burette marked in 0.1 cm³, each reading carries ±0.05 cm³, so a titre volume (two readings subtracted) carries ±0.10 cm³. Express this as a percentage uncertainty against your mean for a genuine Level 7-8 answer.

Look at your processed data, not the raw numbers, and describe direction, rate of change, and any anomalies using specific values pulled straight from your table or graph. "As concentration increased from 0.1 to 0.5 mol dm⁻³, reaction rate increased proportionally" scores far higher than a vague "the rate went up".

Use a line graph with a best-fit line for continuous data, such as concentration against reaction rate. Use a bar chart for discrete or categorical data, such as comparing reactivity across different metals. Always include a title, labelled axes with units, an appropriate scale, and error bars where you've calculated uncertainty.

Level 7-8 requires all five strands done correctly and appropriately — not just attempted: presenting transformed data, interpreting it with sound scientific reasoning, discussing the validity of both hypothesis and method, and describing realistic, relevant improvements. According to the MYP: Sciences guide, Criterion C is marked out of 8 across four achievement bands.

The biggest mark-loser is restating the method instead of analysing results — that belongs in Criterion B, not C. Others include vague trend descriptions with no figures, calculating uncertainty but never referring to it again, and "improvements" that just say "use more accurate equipment" without naming which measurement or why it mattered.

Criterion C evaluates the investigation itself — was the hypothesis supported, was the method valid, what would you change? Criterion D steps back further, asking about the broader impact of the science and technology involved and how your findings connect to real-world issues. They're assessed separately and shouldn't overlap in your write-up.

Criterion C's five strands — presenting, interpreting, evaluating hypothesis and method, suggesting improvements — map closely onto the DP Chemistry Internal Assessment's demands around analysis and evaluation. Students who build solid Criterion C habits in MYP 4-5 generally find the DP IA's data-processing expectations, examined under the current guide with first assessment in 2025, far less daunting.

The most useful thing you can do is ask your child to explain their trend out loud, using actual numbers from their data table, before they write a word — if they can't do that, the write-up won't score well either. Avoid doing the calculations for them; Criterion C rewards independent reasoning, not a polished-looking table.

Practising with real past-style data sets, worked mark schemes, and topical worksheets that isolate each strand — presenting, interpreting, evaluating — builds this skill faster than general revision does. Look for MYP Chemistry resources organised by criterion, so you can target Criterion C specifically rather than revising everything at once.