Edexcel International A-level Computer Science: Command words and keywords

Pearson Edexcel International A-level Computer Science uses the command words defined in the specification. Pseudocode and algorithm questions require correct syntax. A-level expects more depth—data structures, algorithms, complexity.

Command words

Command word	What to do	Common mistake
State	Recall; short answer	Overwriting
Define	Precise computing meaning	Vague
Describe	What the code/process does	Adding explanation
Explain	Why/how	Only describing
Suggest	Apply to context	Generic answer
Compare	Similarities and differences	Listing separately
Analyse	Break down; show relationships	Only describing
Evaluate	Judge; conclude with evidence	No conclusion
Write	Produce pseudocode/algorithm	Wrong syntax
Trace	Follow step by step	Missing steps
Calculate	Work out; show working	Wrong formula

Computing keywords

Term	Use correctly	Avoid
Algorithm	Step-by-step solution	”Code”
Variable	Named storage	”Box”
Array	Collection of same type	List
Procedure	Named block; no return	Function
Function	Named block; returns value	Procedure
Recursion	Function calls itself	”Loop”
Decomposition	Breaking into sub-problems	”Splitting”
Abstraction	Hiding unnecessary detail	”Simplifying”
Big O notation	Time/space complexity	”Speed”
Stack	LIFO	”List”
Queue	FIFO	Stack
Validation	Check data is reasonable	Verification
Verification	Check data is correct	Validation

Tips for Edexcel A-level Computer Science

1. Follow pseudocode guide in specification
2. Trace carefully—show each step
3. Define precisely
4. Suggest—apply to the scenario
5. Past papers + mark schemes show acceptable pseudocode

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Based on Pearson Edexcel International A-level Computer Science specification. Check the latest specification for your exam series.