Does anyone know what the minimum age is for suppossed polygraph accuracy?
There is no peer-reviewed research suggesting that polygraph accuracy declines with subjects below a certain age. But then again, polygraph "testing" has not been proven to work at better-than-chance levels under field conditions with subjects of any age.
If you are the parent or guardian of a child who has been asked to submit to a polygraph "test," it would be wise to refuse permission.