MYP Physics Criterion C: Processing & Evaluating — FAQ

Criterion C, "Processing and evaluating," assesses how you handle data after an investigation: presenting it clearly, identifying trends, drawing a conclusion, and evaluating your method's validity. According to the MYP: Sciences guide, it's marked out of 8 and usually appears alongside Criteria A, B and D in a lab report or extended investigation.

Score well by interpreting your actual numbers (not just describing the graph shape), evaluating validity with real figures like percentage error, and linking your conclusion explicitly back to the hypothesis and accepted physics. Vague statements like "use better equipment" cost marks — examiners want specific, realistic improvements tied to your actual method.

Criterion B, "Inquiring and designing," judges your hypothesis and planned method before you collect data. Criterion C judges what you do with the data afterwards — processing it, spotting trends, calculating error, and evaluating whether your method actually answered the question. Think planning stage versus analysis stage.

Criterion C uses four bands within 0–8: 1–2 (states a basic conclusion with limited data interpretation), 3–4 (outlines a conclusion with some interpretation), 5–6 (describes a conclusion consistent with data, evaluates validity with some detail), and 7–8 (justifies a conclusion using correct scientific reasoning and detailed, realistic evaluation).

Criterion C is marked out of 8, using four achievement bands described in the MYP: Sciences guide. Most subject-group tasks assess all four criteria — A, B, C and D — across a unit, so Criterion C typically appears once per investigation cycle, often via a formal lab report.

A conclusion is consistent with the data when it directly reflects your actual results and trend — not what the textbook says should happen. If your gradient gave an acceleration of 9.6 m/s² and gravity is 9.81 m/s², say that, explain the small discrepancy, and only then relate it to accepted theory.

A strong evaluation does three things: judges the validity of your method using actual data (not opinion), names specific sources of error with reasoning, and proposes a realistic, testable improvement — not just "repeat the experiment." Weak evaluations describe what happened; strong ones explain why it happened and what it means for reliability.

Percentage error compares your experimental value to the accepted (theoretical) value using the formula: percentage error = (|experimental − accepted| ÷ accepted) × 100. Include this figure in your evaluation strand of Criterion C — it's the single clearest piece of evidence that you've genuinely assessed your method's validity.

Random error causes scattered, unpredictable variation in repeated readings — like slightly different reaction times when using a stopwatch. Systematic error shifts every reading in the same direction, usually from a faulty instrument or flawed setup, such as a metre rule with a worn zero end. Naming the correct type earns real marks.

List limitations by working through your method step-by-step and asking where measurement or control could have gone wrong — timing, parallax, temperature drift, sample size. For each limitation, propose one specific, realistic improvement tied to that exact cause, not a generic "be more careful" statement.

Criterion C is internally assessed — your child's own physics teacher marks it against the MYP: Sciences guide descriptors, usually via a lab report or investigation task set during the unit. Schools moderate marking internally, and in MYP eAssessment years, external moderation can apply to on-screen tasks.

Criterion C is one of four criteria (A, B, C, D), each out of 8, that combine into the overall 1–7 MYP subject grade using grade boundaries the school (or the IB, for eAssessment) sets. A consistently weak Criterion C — poor error analysis or unsupported conclusions — can noticeably pull down an otherwise strong physics grade.

That depends entirely on your school's assessment policy — the IB doesn't mandate resubmission for MYP internal tasks. Many schools allow one revision opportunity per criterion per unit, especially in MYP 4–5, but some don't. Ask your physics teacher directly what their retake or resubmission policy actually is.

The fastest gains come from seeing worked, top-band evaluations and practising error calculations on real data sets rather than reading rubric descriptors alone. On revisionprep.com, MYP Physics Revision Notes and Topical Worksheets include sample lab evaluations and percentage-error practice questions matched to the current MYP: Sciences guide criteria.