On a Wednesday evening, Ananya is at the dining table with a practical write-up due on Friday. The reaction-rate experiment went fine in the lab, but her draft says 'add the acid' in the method and ends its conclusion by repeating the table. Her father has read it twice and asks the question many families eventually ask: what do the teachers actually want to see?
The short answer is that Criterion B is won or lost before the first measurement, through a testable question, clearly named variables and a method someone else could repeat. Criterion C rewards what happens after the data arrives: careful processing, graphs that show the pattern, a conclusion tied to the evidence and an evaluation that names real limitations and realistic fixes.
Why Criterion B is decided before the first measurement
Most students treat the investigation question as a formality. In practice it sets the ceiling for everything else. A question such as 'How does temperature affect the rate of reaction?' is too loose to test. Something like 'How does changing the water bath temperature between 20 and 60 °C affect the time taken for the reaction to reach a fixed colour change?' tells the reader exactly what will be measured and what will be held steady.
Name every variable, including the boring ones
Write down the independent variable, the dependent variable and at least three controlled variables, and say how each one will be kept constant. Volume of solution, concentration, stirring and timing method are the usual suspects. Examiners notice when a student has thought about the things that could quietly spoil the result, and it is often the difference between a middling and a strong Criterion B.
A method another student could follow on Monday
A good method reads like a recipe written by someone who expects to be questioned. Each step should specify quantities, equipment sizes and timings, and it should say what to do if something goes wrong, such as a reading that drifts. Add a short risk assessment that goes beyond 'be careful with acids', naming the specific hazard and the control, like wearing goggles when handling dilute hydrochloric acid and rinsing spills immediately.
- State the apparatus with measurements, not just names.
- Number the steps in the order you actually performed them.
- Explain why you chose the number of repeats and the range of values.
Processing data without losing the thread
Criterion C starts with the raw numbers. Keep the original table exactly as recorded, then add processed columns such as averages, rates or percentage change, with the formula shown once. Calculated uncertainties belong here too. If you took three readings per temperature, show the spread, not just the mean.
Graphs deserve the same care. Choose a scatter plot for continuous variables, label both axes with units, and plot error bars where you have them. A line of best fit should follow the trend you are describing, not a line drawn through the first and last points for convenience. One clean graph that shows the pattern will usually do more for your mark than three crowded ones.
Conclusions and evaluations that argue rather than summarise
A conclusion is not a restatement of the results. It should answer the investigation question directly, cite specific numbers from your processed data and compare them with what the scientific model predicts. If your data did not fit the expected pattern, say so and suggest why.
The evaluation is where many students lose marks. Vague lines such as 'human error' or 'the experiment could be improved' earn little credit. Stronger evaluations name a specific limitation, explain how it affected the data (for example, heat loss from an open beaker making the higher temperatures read faster than they should), and propose a change that would address it. Suggest one or two improvements that you could realistically carry out with the same equipment.
Building the habit across a term
Lab reports go better when the writing starts in the lab, not the night before. Many families find a simple routine helps:
- Write the investigation question and variables before the practical starts.
- Draft the method while it is still fresh, noting every deviation from the plan.
- Process data the same day, while you can still ask the teacher about an odd reading.
- Leave the evaluation until you have seen the graph, because the weaknesses become obvious then.
Students who struggle with this often need feedback that is specific to a criterion, not a single grade at the bottom of the page. At our tuition centre in Kokapet, MYP Science is taught in small batches of four to eight, so teachers can check each student's planning before the lab and go through the processing and evaluation of their reports afterwards. Our teachers mark against the published MYP criteria and command terms, which means the feedback tells a student exactly which step of a criterion to strengthen. You can read more about our IB MYP tuition programme and the approach behind it, or find further practical guides in the Inacademics blog.
Frequently Asked Questions
How long should an MYP Science lab report be?
There is no fixed word count in the criteria. Length should follow what the criteria ask for: a clear question, a repeatable method, processed data, a supported conclusion and a specific evaluation. Padding does not earn marks. Clarity and precision usually matter more than the number of pages, so check your school's guidance on format and length.
Do I need to include error bars on my graph?
Where you have repeated measurements, error bars show how reliable your results are, and they make the evaluation far more convincing. Calculate the spread from your repeats and explain briefly how you worked it out. If the readings are a single measurement, say so and discuss how that limits what you can conclude.
How does INACADEMICS help students who lose marks on Criteria C?
We start with a short diagnostic to see which part of the report is holding the mark back, whether that is data processing, graphing or evaluation. The student then works in a small batch with a subject specialist who marks drafts against the MYP criteria. Parents receive regular updates tracked against the student's plan, so progress is visible rather than guessed at.
Can a tutor write the lab report for my child?
A good tutor should not. The aim is for your child to understand what each criterion rewards and to practise it until the habit sticks. At INACADEMICS our teachers guide students through the reasoning, ask questions about their data and point out weak sentences, but the writing and the thinking stay with the student.
Every family's situation is different, and a short conversation can show whether the support fits. You can book free counselling by phone or WhatsApp on +91 9014010410, or visit us at 117, 1st Floor, Raichandani Business Bay in Kokapet, above Karachi Bakery. We will look at your child's current reports, identify the criterion costing the most marks and suggest a sensible starting point, with no obligation to join.