Subjects, levels and exam boards Marky marks
Marky marks maths, biology, chemistry and physics at GCSE, AS and A-Level, against the official mark scheme uploaded with the papers. This page sets out what marking each of those subjects involves, which levels and boards are covered, and what is not supported yet.
Subjects
Maths, Biology, Chemistry, Physics
Levels
GCSE, AS and A-Level
Exam boards
AQA, Pearson Edexcel, OCR, WJEC/Eduqas, CCEA
Marking mathematics
In mathematics the working carries as much credit as the final answer, and a marker who reads only the answer box will mark most papers wrongly.
Mark schemes split a question into method marks, accuracy marks and independent marks. A candidate who selects a valid method, sets the working out correctly and then makes a single arithmetic slip is entitled to the method credit even though the final line is wrong. Follow-through compounds this: where a scheme allows it, a value carried forward from an earlier error has to be accepted, and every subsequent step judged against that value rather than against the correct one. Marking a paper strictly on the final answer under-awards the students who understood the mathematics and made one mistake.
Marky transcribes the whole of a candidate's working, line by line, including work written in the margin, continued on a spare page or attempted twice. Each intermediate line is matched against the method points in the scheme, so credit is awarded where the scheme awards it. Equivalent forms are treated as equivalent: an unsimplified surd, a fraction rather than a decimal, a factorised rather than an expanded expression, and answers given to a different but acceptable precision. Crossed-out work is handled the way the exam boards require, so a replaced attempt is not double counted and a crossed-out attempt that is the only work present is still read.
Mathematics is also the largest part of the published accuracy measurement, at 1,904 GCSE sections and 638 AS sections.
What is read on a maths script
- Method marks awarded on the working, independently of whether the final answer is correct
- Follow-through applied where the scheme allows it, so one early slip does not cost the whole question
- Equivalent forms accepted: surds, fractions, factorised expressions and alternative valid methods
- Graphs, diagrams and constructions read from the page rather than inferred from the surrounding text
- Overflow working in margins and on continuation pages attributed to the right question
Marking biology
Biology is the most heavily written of the four subjects, and the marking problem is one of judgement rather than arithmetic.
A six mark explanation is marked against a list of scheme points, each with its own permitted alternatives and its own explicit refusals. Candidates almost never use the wording printed in the scheme. They express the right biology in their own words, in a different order from the scheme, sometimes spread across two paragraphs and sometimes buried inside an answer that also contains something incorrect. The marker has to decide, point by point, whether the required idea is present, whether a required technical term has genuinely been used, and whether an incorrect statement elsewhere in the answer cancels a point that was otherwise earned.
Marky assesses each scheme point independently against the transcribed answer rather than comparing the answer to a model paragraph as a whole. That matters on longer items, where a strong answer written out of order would otherwise lose marks for presentation rather than for biology. Practical questions carry the same treatment: independent and dependent variables, controls, and the reasoning about validity are marked as separate points because the scheme awards them separately. The feedback returned with each question quotes the part of the script the decision rests on, which makes a disputed mark quick to check.
The published accuracy figures below cover the mathematics and physics cohorts. Biology has not yet been measured against a verified examiner at the same scale, so a department considering biology is encouraged to benchmark it on its own already-marked papers during the trial.
What is read on a biology script
- Each mark scheme point judged separately against what the candidate wrote, in whatever order it was written
- Allowed alternatives and refusals taken from the scheme rather than from a generic rubric
- Required terminology distinguished from loose paraphrase, for instance osmosis against diffusion
- Data response answers checked against the figures in the table or graph the question supplied
- Feedback that quotes the script, so the sentence responsible for a withheld point is visible
Marking chemistry
Chemistry papers mix short recall, symbol equations and multi-step quantitative work, and each of the three is marked on different grounds.
Equations are unforgiving. A symbol equation earns credit only if the formulae themselves are correct, and an equation that balances perfectly around a wrong formula earns nothing at all. Where the scheme demands state symbols, they are part of the mark. Half equations for electrolysis add electrons and charge to the same test. This is a category of question where a marker reading quickly, or a system that only compares strings, produces the wrong result, because the answer looks superficially close to the scheme.
Moles calculations are the other characteristic case. A typical item runs from mass and relative formula mass to moles, applies a stoichiometric ratio, and converts back to a mass, a concentration or a gas volume. The final answer is expected in stated units and to a stated number of significant figures. The scheme normally splits marks across those stages. Marky marks the stages, so a candidate who calculates the moles correctly and then applies the wrong ratio keeps the marks already earned. The feedback names the stage where the chemistry went wrong rather than reporting that the answer was incorrect. Titration calculations, percentage yield and atom economy are handled the same way.
As with biology, chemistry does not yet appear in the published accuracy cohorts, and the trial is the appropriate way to test it against a department's own marked papers.
What is read on a chemistry script
- Symbol equations checked for correct formulae first, then for balancing and for state symbols where required
- Moles calculations marked stage by stage: moles, ratio, conversion, units and significant figures
- Half equations assessed for species, electrons and charge balance together
- Titration, yield and atom economy credited for correct method even where the final figure is wrong
- Structures and mechanisms read as drawn on the page, including displayed formulae
Marking physics
Physics is dominated by multi-step calculation, and units and significant figures are marks in their own right.
A four mark calculation commonly awards one mark for selecting the correct relationship, one for rearranging it, one for a consistent substitution of values, and one for the final answer expressed in the correct unit. A candidate can therefore produce a numerically correct figure and still lose a mark by quoting it in millimetres rather than metres, or to four significant figures where the data supports two. The reverse is equally common: an answer that is numerically wrong because of a slip in the third line still holds three of the four marks, provided the physics up to that point was sound.
Marky evaluates those components separately. The relationship used, the substitution, the arithmetic, the unit and the stated precision are each checked against the scheme, and prefix conversions and standard form are resolved before the comparison is made. Where a value has to be read off a graph, the tolerance printed in the scheme is applied rather than a single expected figure. Multiple choice items are decided from the mark actually made on the paper, which avoids the failure mode of inferring an intended answer from adjacent working.
Physics accounts for 668 A-level sections and 66 AS sections in the published measurement, and at AS and A-Level every section fell within two marks of the verified examiner.
What is read on a physics script
- Equation selection and rearrangement credited separately from the arithmetic that follows
- Units checked on the final answer, including prefix conversions and standard form
- Significant figures assessed against the precision the question and scheme require
- Values read from graphs accepted within the tolerance the scheme states
- Multiple choice responses read from the mark on the page rather than inferred from nearby working
Levels: GCSE, AS and A-Level
All four subjects are supported at all three levels. The level determines the grade scale applied to a total, and that scale is taken from the boundaries configured for that paper.
GCSE
Grades 9 to 1, Foundation and Higher tiers
Tier is set per paper, because the two tiers overlap in content but not in expectation and carry different boundaries. A Foundation script and a Higher script answering the same topic are marked against their own scheme and converted on their own boundaries, so a mixed-tier class set can be uploaded together.
AS
Grades A to E
AS papers are marked on the same two-pass process as every other level. In the published measurement, AS mathematics reached 94.67% exact agreement across 638 sections, the highest of the four cohorts, and no AS section fell more than two marks from the examiner.
A-Level
Grades A* to E
A-Level papers carry the longest multi-step items and the widest mark ranges, which is where method credit matters most. A-level physics contributed 668 sections to the published measurement at 92.37% exact agreement.
Exam boards
Marky marks papers from all five UK exam boards. Marking is performed against the official mark scheme uploaded with the papers, so board-specific conventions come from the scheme itself.
AQA
GCSE, AS & A-Level
Pearson Edexcel
GCSE, AS & A-Level
OCR
GCSE, AS & A-Level
WJEC/Eduqas
GCSE, AS & A-Level
CCEA
GCSE, AS & A-Level
Grade boundaries are configurable per paper and per year
Boundaries move between series, and a total that was a grade 7 in one year is not necessarily a grade 7 in the next. For that reason boundaries are held per paper and per year rather than as a single national table, and a department can set them for the exact paper being sat. A mock marked on last year's boundaries and the same mock marked on this year's produce different grades from identical marks, which is a source of confusion worth removing before results are shared.
Because marking is driven by the uploaded mark scheme rather than a fixed internal rubric, past papers, mock papers and department-written assessments are treated the same way. What matters is that a mark scheme accompanies the papers. The upload and marking process is identical in each case, and papers arrive as PDFs or as photographs taken on a phone, in .jpg, .png, .heic or .webp, with no conversion required.
Measured accuracy by cohort
Across 3,276 question sections marked by a verified examiner, spanning mathematics at GCSE and AS and physics at AS and A-level, 99.8% of Marky's marks fall within two marks of the examiner's, 98.9% within one, and 92.4% are exactly the same mark. Section counts are published because a percentage without a denominator is not evidence.
| Cohort | Sections marked | Exactly the same mark |
|---|---|---|
| GCSE mathematics | 1,904 | 91.75% |
| AS mathematics | 638 | 94.67% |
| A-level physics | 668 | 92.37% |
| AS physics | 66 | 87.88% |
Two independent marking passes
Every paper is marked twice. Disagreements between the passes are resolved before the mark is released, and the reasoning stays attached to the question so any decision can be checked.
Six stated reasons for review
Papers needing human attention are flagged with the reason: near a grade boundary, handwriting that could not be read confidently, a possible integrity concern, disagreement between marking passes, arbitration, or wide variance.
The most useful comparison remains a department's own. See how this compares with manual marking, or review the per-paper pricing at £1.20 per marked paper.
What is not supported yet
The supported list is exactly four subjects: maths, biology, chemistry and physics, at GCSE, AS and A-Level. Anything outside that list is not available today, and it is more useful to say so than to imply otherwise.
English, the humanities, modern languages and the remaining sciences are not marked. The reason is not that the technology is confined to numerical subjects, since biology already involves extended written explanation judged against mark scheme points. It is that a subject is only added once its marking has been measured against verified examiner marks on a real cohort, and that measurement takes a body of already-marked papers to build. Adding a subject before that work exists would mean asking departments to trust an unmeasured claim.
The same principle applies within the supported subjects. Mathematics and physics carry published per-cohort figures. Biology and chemistry are supported and marked on the same two-pass process, but their accuracy has not yet been published at the same scale, which is stated plainly above rather than left to inference.
How to request a subject
Requests are made through the contact form. Naming the subject, the level and the exam board is enough for a request to be assessed. A note of approximately how many papers a year the department marks helps with prioritisation, since subjects are added in the order that departments ask for them.
Departments already teaching a supported subject can test the marking directly. The free 3-day trial requires no card, and the most informative use of it is a set of papers that has already been marked by hand, compared question by question against the marks the department awarded.
Subject and exam board questions
Which subjects does Marky mark?
Which exam boards are supported?
Are Foundation and Higher tier GCSE papers both marked?
Does maths marking give credit for working?
Has accuracy been measured for every subject?
How long does a class set take to mark?
Every supported subject is included in the trial
Free for 3 days, no card required for schools. Papers are £1.20 each thereafter, bought as an annual department allowance from 1,000 papers.