How the Interpreting Diagrams test works
EEI describes the test as using symbols and codes to locate objects on a map or diagram and to determine each object’s status. In the brochure example the map is divided into labelled sectors, and a legend explains symbols for equipment such as pumping units and shut-off valves.
Questions ask things like how many of one symbol appear in a sector, or what state a particular object is in, with four answers. EEI does not publish how many questions there are or how long you get.
How to read a sector map
A careful routine prevents nearly every error on this test:
- Read the legend first and note any symbols that differ only by fill, outline or a small mark.
- Find the sector boundaries before counting. Symbols sitting on a boundary are the usual trap.
- Count with your pencil, ticking each symbol once, rather than counting by eye.
- For status questions, find the object first, then check the legend for its exact variant.
- If your count is one away from an option, recount before choosing.
Worked example
Legend: a triangle is a transformer, a filled circle is a closed switch and an empty circle is an open switch. Sector B2 contains 3 triangles, 2 filled circles and 4 empty circles.
Question: how many switches in sector B2 are closed? A: 2. B: 4. C: 6. D: 9. Only filled circles are closed switches, so the answer is A. C counts every switch, and D counts every symbol in the sector.
Tips for the real Interpreting Diagrams test
- Keep the legend in view the whole time. Do not rely on memory for similar symbols.
- Read the question for the sector and the status it asks about, not just the object type.
- Work at a steady pace. Accuracy matters more than speed on counting questions.
- Fill in an answer for every question before time is called.
Practise Interpreting Diagrams on CogniPrep
Our version uses generated sector maps with a symbol legend and 20 questions in 15 minutes, a clock we set because EEI publishes none. Each map carries several questions with four options, on counts by sector and the status of particular objects. Navigation is free until you hand in from the review grid, and your score out of 100 counts every question on the paper.