litmus tests
Pass-or-fail indicators
A litmus test is literally a chemical test using treated paper that turns red in acid and blue in base.
Figuratively, it's a single decisive factor that determines an outcome or reveals someone's position: Abortion rights have become a litmus test for Supreme Court nominees.
The metaphor emphasizes that complex questions are being reduced to one criterion.
- acidLow-pH chemical compound
- dealbreakerUnacceptable condition that ends talks
- red lineInviolable boundary or threshold
- testEvaluative examination
- pass or failBinary grading system
indicator · benchmark · touchstone · base · criterion · shibboleth · gauge · vetting · purity test · loyalty oath · standard · make or break · integrity · pH · non-negotiable · single issue · assessments · gatekeeping