IB MYP Sciences: The Four Assessment Criteria in Practice

This guide works through what genuinely top-band evidence looks like for each of IB Middle Years Programme Sciences’s four assessment criteria, applied to real coursework tasks. The assessment revision notes list the four criteria and their scoring structure – this guide goes further, since knowing a criterion’s name is a different skill from producing investigative work that satisfies its top achievement-level descriptors.

Where this fits in the subject

Because schools can deliver MYP Sciences as discrete subjects – separate biology, chemistry, physics – a modular course, or a fully integrated science course, the four criteria’s descriptors stay identical regardless of which model your school uses – what changes is only the specific scientific content an investigation draws on. A student in a discrete-biology class and a student in an integrated-science class are held to the exact same Criterion B (inquiring and designing) or Criterion C (processing and evaluating) standard; revision of the criteria themselves therefore transfers directly across course models even where the underlying content differs.

Criterion A: Knowing and understanding

Top-band evidence develops and applies scientific knowledge – facts, ideas, concepts, processes, laws, principles, models and theories – to solve problems and express scientifically supported judgments, not simply recalling a definition, but using that knowledge to reach and justify a conclusion in an unfamiliar context. Asked to explain why a metal spoon feels colder to the touch than a wooden spoon at the same room temperature, top-band evidence does not stop at naming “thermal conductivity” – it applies the concept of conduction rate to explain why heat transfers away from the hand faster through the metal, and uses this reasoning to make a scientifically supported judgment about the actual temperature, which is identical, versus the perceived temperature, which is different.

Criterion B: Inquiring and designing

Top-band evidence designs, analyses and performs a genuine scientific investigation – meaning the student formulates their own testable research question and hypothesis, identifies variables to control, and justifies their chosen method, rather than simply following a prescribed worksheet procedure. A lower-band task might follow fixed instructions to measure how temperature affects reaction rate. Top-band Criterion B evidence instead involves the student proposing their own specific, testable research question – how does the concentration of a particular reactant affect reaction rate under otherwise controlled conditions, for example – justifying why the chosen variables should be controlled, and explaining the reasoning behind the chosen method before carrying it out.

Criterion C: Processing and evaluating

Top-band evidence collects, processes and interprets qualitative and/or quantitative data accurately, and explains conclusions properly reached from that data – including identifying limitations in the data or method and suggesting genuine, specific improvements, not generic ones like “use more trials.” After collecting reaction-rate data across several concentrations, top-band evidence presents the data in an appropriately labelled graph, correctly identifies the trend, explains that trend using the relevant scientific concept, such as collision theory, and then evaluates a specific limitation of the actual method used – that reaction start-time was judged by eye, introducing timing error, for example – with a specific, targeted improvement, such as using a colorimeter to detect the reaction’s endpoint automatically, rather than a vague suggestion.

Criterion D: Reflecting on the impacts of science

Top-band evidence evaluates the implications of scientific developments and their applications to a specific problem or issue, using varied scientific language and properly documenting the work of others – meaning genuine evaluation of real-world impact, not a one-sided description of only benefits or only risks. Asked to discuss the impact of a specific agricultural technology, such as genetically modified crops, top-band evidence presents both a genuine benefit, such as increased crop yield in specific conditions, and a genuine limitation or risk, such as ecological or economic concerns raised in published sources, properly cited, reaching a reasoned evaluative judgment rather than presenting only one side or a purely descriptive account of the technology.

Why the four criteria are usually assessed through one connected investigation

A single well-designed practical investigation typically generates evidence for all four criteria at once: the scientific concept underpinning the investigation (Criterion A), the design of the investigation itself (Criterion B), the processing and evaluation of the resulting data (Criterion C), and, where relevant, a reflection on the investigation’s broader scientific or real-world significance (Criterion D). Revising each criterion as a fully separate skill, rather than practising a complete investigation that touches all four, risks preparing for an assessment structure that does not match how MYP Sciences coursework is actually usually set.

How to approach it

Practise applying scientific concepts to unfamiliar contexts rather than only reciting definitions, since Criterion A specifically rewards transfer. Formulate your own testable research questions and justify variable and method choices, rather than treating a prescribed procedure as the ceiling of Criterion B evidence. Practise identifying one specific limitation of an actual method used and proposing an equally specific, targeted improvement, rather than defaulting to generic suggestions Criterion C does not credit. Build the habit of presenting a genuine two-sided evaluation – a real benefit and a real risk or limitation, each properly sourced where relevant – for Criterion D, rather than a one-sided account. Where possible, practise a complete investigation touching all four criteria at once, since this reflects how MYP Sciences coursework is typically structured.

Official syllabus

International Baccalaureate Organization, Middle Years Programme Subject Brief – Sciences, from 2014, (c) 2015 – the same source already cited by the full syllabus guide and the revision notes already on the site. Verified 2026-09-06.