Glossary · 7 · Evaluation methods
Symbol comprehension test
Also known as: Comprehension test (graphical symbols), Comprehensibility test for symbols, Symbol comprehensibility test
German: Verständlichkeitsprüfung von Symbolen
A symbol comprehension test is a standardized procedure for measuring the extent to which a graphical symbol or a safety sign using one communicates its intended meaning to the intended users without supplementary text; ISO 9186-1:2014 specifies the method used in international standardization of graphical symbols.
- Applied cognitive psychology
- Evaluation methods
- Standards
In one sentence
A symbol comprehension test measures how well a graphical symbol or safety sign conveys its meaning without text; ISO 9186-1:2014 sets the method.
Example
A manufacturer plans a new symbol for “stored hydraulic pressure”. In a comprehension test, participants from the target countries see the symbol in context and write what it means; answers are scored against the intended meaning, and the variant with the highest correct rate and fewest critical confusions is chosen.
Rests on
- Recognition and recall and Long-term memory: users interpret a symbol by matching it to what they know; unfamiliar symbols are guessed.
- Cognitive schema and prototype theory: a symbol works when it evokes the intended category for the users, which differs between cultures and experience.
How it applies
- The standard: ISO 9186-1:2014 (second edition, ISO/TC 145) specifies a method for testing the comprehensibility of graphical symbols, giving a measure of how far a variant communicates its intended message. It aims at symbols that are understood without supplementary text; where that cannot be achieved, the symbol may need to be shown with explanatory text in the users' language. Further parts cover perceptual quality (ISO 9186-2) and referent association (ISO 9186-3).
- Safety signs and product symbols: New safety sign and symbol designs are tested before standardization; manufacturers who create their own symbols can use the same method. In the United States, ANSI Z535.3 sets criteria for safety symbols.
- Documentation: Symbols used in instructions, on labels and on the HMI should be standardized ones where they exist, with a legend; self-made symbols need testing.
Limits
- A test shows comprehension under test conditions; recognition at a distance, under time pressure or in poor light needs other tests (ISO 9186-2).
- A well-understood symbol does not make a warning sufficient; text with hazard, consequence and avoidance is often needed, as decided by the risk assessment and the applicable standards.
- The test does not show that a product or sign complies with any legislation.