We disclose a health metric validation system in which a first heath metric is taken which is a measurement that is relevant to a user's health status. The first health metric may be used to diagnose a disease. A second metric is collected from the user and used to validate the first health metric. The first health metric and the second metric are entered into a computer which applies a first set of rules to the first health metric and second metric. The computer calculates a weight value and assigns it to the first health metric. The computer applies a second set of rules to the first health metric and its weight value to calculate an indicator value. The indicator value provides an indication of the validity of the first health metric.