Learn iGCSE Biology — Edexcel 4BI1 spec points

← Home
📋 Review

Select a topic from the sidebar to begin.

Core Practicals — CORMS Framework

The CORMS Framework

C
Control variables
What you keep the same, and why
O
Outcome
The dependent variable — what you measure and how
R
Range & Repeats
How many values tested; how many repeats for reliability
M
Manipulation
The independent variable — what you change
S
Safety
Hazards identified and precautions taken

General Exam Advice

  • Always name the independent variable and dependent variable explicitly.
  • For control variables, say what AND why.
  • Repeats improve reliability; a control experiment improves validity.
  • When describing a trend, quote actual values from the data.
  • Anomalous results should be identified and excluded from the mean.
  • "Fair test" alone is not enough — always say what was kept the same.
  • Risk assessments need a hazard, the risk it poses, and the precaution taken.