Edexcel IGCSE Computer Science: Command words and keywords

Pearson Edexcel International GCSE Computer Science (4CP0) uses the command words defined in the specification. As with Cambridge, pseudocode and algorithm questions require correct syntax and structure. Check the Edexcel specification for the exact pseudocode conventions used.

Command words in Edexcel Computer Science 4CP0

Command word	What to do	Common mistake
State	Recall; short answer	Overwriting
Identify	Choose from code/diagram	Adding explanation
Define	Precise computing meaning	Vague
Describe	What the code/process does	Adding explanation
Explain	Why or how; use “because”	Only describing
Suggest	Apply to context; propose	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
Outline	Main points	Too much detail

Pseudocode and programming keywords

Edexcel uses its own pseudocode conventions—check the specification. Common concepts:

Data types

Term	Use correctly	Avoid
Integer	Whole numbers	Real
Real	Numbers with decimal	Integer
String	Text/character sequence	Char (single)
Boolean	True/False	”Yes/No”
Character	Single character	String

Control structures

Term	Use correctly	Avoid
IF … THEN … ELSE	Conditional	Wrong structure
WHILE	Pre-condition loop	REPEAT when different
REPEAT … UNTIL	Post-condition loop	WHILE when different
FOR	Count-controlled loop	Wrong loop type
Procedure	Named block; no return	Function
Function	Named block; returns value	Procedure
Parameter	Input to procedure/function	”Input”

Programming concepts

Term	Use correctly	Avoid
Algorithm	Step-by-step solution	”Code”
Variable	Named storage; can change	”Box”
Constant	Named storage; fixed	Variable
Array	Collection of same type	List (Python)
Iteration	Repeating (loop)	“Loop”
Selection	IF/CASE	”If”
Sequence	Steps in order	”Order”

Hardware and data

Term	Use correctly	Avoid
CPU	Central Processing Unit	”Processor”
RAM	Random Access Memory; volatile	ROM
ROM	Read-Only Memory; non-volatile	RAM
Binary	Base 2	”Off/on”
Hexadecimal	Base 16	”Hex”
Bit	Binary digit; 0 or 1	”Digit”
Byte	8 bits	”8 bits”
Compiler	Translates whole program	Interpreter
Interpreter	Translates line by line	Compiler
Decomposition	Breaking into sub-problems	”Splitting”
Abstraction	Hiding unnecessary detail	”Simplifying”
Validation	Check data is reasonable	Verification
Verification	Check data is correct	Validation

Edexcel marking principles

• Apply positively—reward what candidates show.
• Pseudocode—follow specification conventions exactly.
• Trace—show each step; method marks available.
• Define—precise computing definitions.
• Suggest—apply to the scenario.

What examiner reports highlight

• Pseudocode syntax—wrong structure or keywords lose marks.
• Trace—errors cascade; show every step.
• Describe vs Explain—description when explanation required.
• Define—vague or everyday language.
• Suggest—generic instead of applied.

Tips for Edexcel Computer Science 4CP0

1. Learn the pseudocode guide in the specification.
2. Use correct keywords—check the exact syntax.
3. Indent nested structures clearly.
4. Trace carefully—initial values and each step.
5. Define precisely—e.g. “An algorithm is a step-by-step procedure to solve a problem.”
6. Past papers + mark schemes show acceptable pseudocode.

How Tutopiya helps

Tutopiya supports Edexcel IGCSE Computer Science with tutors who use the specification and past papers. Explore IGCSE resources or book a free trial.

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Based on Pearson Edexcel International GCSE Computer Science 4CP0 specification. Check the latest specification for your exam series.