How AS & A Level Computer Science (9618) is marked
Computer Science 9618 runs across twelve papers, and it is almost entirely point-marked: 1,492 of 1,501 questions in our bank earn marks point by point, with only 9 marked by calculation. This matters for how you should write code and pseudocode answers — each mark corresponds to a specific, checkable feature of your solution (a correctly closed file, a returned value, a parameter passed rather than hardcoded), so a program that 'basically works' can still miss several discrete marks if individual required elements are absent.
The programming papers (41-43) test whether your code does exactly what the question specifies, in the structure specified — using a function when a function is asked for, a recursive call when recursion is required, the correct parameter rather than an input statement. Papers 21-23 and 31-33 test theory and written explanation with the same point-by-point discipline: a description needs to name the actual mechanism, not gesture at it.
Because marking is point-based rather than holistic, marks are typically lost not through wrong logic overall but through one missing procedural step — a file opened but never closed, a loop that runs the wrong number of times, a constructor that does not call its parent. Precision in following the exact structure asked for is worth more here than an elegant but non-conforming alternative.
Where candidates actually lose marks
- Opening a file to read data but never closing it, or writing the function header without returning the populated array it built. (try the question)
- When implementing a logic circuit from a boolean expression, misplacing the NOT gate on the wrong sub-expression or omitting the final NOT gate that inverts the whole expression. (try the question)
- When asked for a recursive algorithm, writing an iterative solution instead — with no recursive call at all, often just repeating the earlier iterative answer. (try the question)
- When inserting data into a queue, inserting at the wrong position (for example incrementing the tail pointer before rather than after inserting) or failing to update the head pointer for the first item added. (try the question)
- Creating a subclass that does not correctly use inheritance — building the constructor with the right parameters but assigning values to attributes directly instead of calling the parent constructor. (try the question)
- Not limiting a value to its maximum correctly before updating dependent values, so an out-of-range input propagates into later calculations instead of being capped first. (try the question)
- Manually reading values for each item instead of calling the correct method on each object, so the required method is never actually invoked once per object. (try the question)
Command words in AS & A Level Computer Science
| Command word | Times in our bank | What it demands |
|---|---|---|
| Write | 334 | The most frequent command word — requires a working program or algorithm in the required structure (function, procedure, recursive call) rather than any code that produces the right output. |
| State | 234 | Wants a brief, precise fact — a value, a term, or a single-line answer — with no development needed or credited. |
| Describe | 169 | Needs an accurate account of how something works using correct technical terms, not a general or everyday explanation. |
| Explain | 159 | Requires reasoning about why something happens or is needed, connecting cause to effect in the underlying computer science. |
| Complete | 149 | Asks you to fill in a gap in given pseudocode, a diagram, or a table so the whole piece functions correctly and consistently with what is already there. |
| Identify | 119 | Requires picking out a specific correct item, term, or line, often from code, a diagram, or a set of options. |
| Draw | 59 | Used for logic circuits, diagrams and structures, where standard symbols and correct wiring are both marked, not just the overall shape. |
| Show | 51 | Wants worked evidence of a process — such as trace tables or intermediate steps — not just a final answer. |
How to revise with past papers
Because nearly every mark in this subject is a discrete, checkable feature, practise past papers by running your code (or tracing your pseudocode by hand) and checking off each required element against the mark scheme individually, rather than judging your answer as 'right' or 'wrong' overall. A program that produces correct output but skips a required structural feature — closing a file, using a parameter instead of an input — will still lose marks even though it 'worked'.
When a question specifies a technique (recursion, a particular data structure, object-oriented inheritance), treat that specification as a hard requirement rather than a suggestion: a correct-looking but non-conforming solution (an iterative fix instead of recursion, a subclass that never calls its parent constructor) scores poorly despite reasonable logic, because the marks are for the specified structure.
Keep a personal checklist of the procedural slips that are easy to make — opening without closing files, forgetting to update a pointer, omitting the self parameter in Python — and specifically hunt for them when reviewing your own completed papers, since these are exactly the kind of small, repeatable mistakes targeted practice can eliminate.
Practise real 9618 questions with AI marking →FAQs
Is partial credit available if my program does not fully work?
Yes — because marking is point by point (1,492 of 1,501 questions in our bank), individual correct elements such as a correct loop structure or a correct parameter list can still earn marks even if the whole program does not run correctly.
Does it matter which programming language I use?
The mark schemes are designed to be language-neutral, but language-specific slips are easy to make (such as omitting 'self' in Python methods, or adjusting loop end-values when translating from pseudocode), so know the small conventions of your chosen language precisely.
What is the single most common way marks are lost?
Missing one required structural step while getting the overall logic right — not closing a file, not returning a value, not calling a required method for every object — rather than misunderstanding the underlying concept.
Which command word appears most often?
Write is the most frequent, reflecting how much of this subject is assessed through producing working code or algorithms rather than describing concepts in prose.