Criterion: a standard of judgment or criticism; a rule or principle for evaluating or testing something
Since values are typically abstract and subjective, we need to have a way to measure them (how can you determine if one side is more "moral" or more "equal" than the other?). The way we measure the value is called the criterion (or value criterion [VC], or value standard). The value is what we want to achieve, the value criterion is how we can achieve it or how we know we achieve it
Your criterion will often be [verb + object], such as protecting life, minimizing suffering, rejecting violence, encouraging participation, etc.