MYP Chemistry Criterion C: Processing & Evaluating FAQ

You score well by doing exactly what each strand asks: present data clearly (tables, graphs, correct units), process it accurately (calculations, trends, uncertainty), then evaluate — comment on validity, reliability and improvements. Most lost marks come from skipping the evaluation strand entirely, not from bad data.

Criterion C, Processing and evaluating, is one of four MYP Sciences criteria (A Knowing, B Inquiring, C Processing, D Reflecting), assessed out of 8 marks at MYP 4-5. It measures how well a student handles collected data — presenting it, processing it mathematically, and judging how trustworthy the results actually are.

The three strands are: (i) collect and present data in appropriate forms — tables, graphs, correct significant figures; (ii) accurately process the data using appropriate mathematical operations, including uncertainty where relevant; (iii) interpret results and evaluate the validity of a hypothesis or method against scientific reasoning.

Level 5-6 usually means you're processing data correctly but not evaluating it. That top band (7-8) needs a genuine discussion of validity — random and systematic error, whether the sample size was enough, and improvements tied to an actual weakness in your method, not a generic "use more trials".

Processing is the maths: calculating averages, rates, percentage change, or plotting a best-fit line from your raw data. Evaluating is the judgement: deciding whether that processed data actually supports your hypothesis and whether your method was reliable enough to trust the conclusion.

A strong evaluation names a specific strength and weakness of your method, links each to its actual effect on the data, and proposes a realistic, testable improvement — not "repeat the experiment" but exactly how and why that would reduce error.

Percentage uncertainty is (instrument uncertainty ÷ measured value) × 100. For a burette reading to ±0.05 cm³ over a titre of 24.55 cm³, that's (0.05/24.55) × 100 ≈ 0.2%. Showing this calculation, not just quoting the instrument's resolution, is what moves you into the top mark band.

Criterion B assesses your planning — the hypothesis, variables, and method design, before you collect any data. Criterion C only kicks in once you have results: how you present, process and evaluate them. A brilliant plan (high B) can still earn a low C if the data write-up is weak.

Criterion C is marked out of a maximum of 8, on the same 0-8 scale as Criteria A, B and D in MYP Sciences. Schools convert the total of all four criteria (out of 32) into the MYP 1-7 grade using their own grade-boundary conversion, so exact boundaries vary school to school.

Expect "process", "interpret", "evaluate" and "discuss" most often. "Process" wants a calculation or transformation of raw data; "evaluate" wants a judgement with reasoning; "discuss" wants both sides of an argument — for example, strengths and weaknesses of your method — not just a description.

Not necessarily every single unit, but the MYP Sciences guide requires each of the four criteria to be assessed at least twice per year across MYP 4-5, using at least two different task types. Your child's school builds this into its own assessment plan, so check the year's unit planner for exactly when Criterion C tasks fall.

The best practice is repeated, low-stakes data-processing: taking a sample data set and writing the evaluation paragraph alone, timed. On RevisionPrep, Topical Worksheets and Mock Papers give MYP-style data sets with mark schemes, so your child can check their evaluation against what examiners actually reward before the real assessment.