If you have one, what is your standard for measuring human worth?
How well a person embraces the UU First Principle: The inherent worth and dignity of every person.
Not every white male; not every Christian (almost an oxymoron, as Christian theology teaches all are sinners;) not every Buddhist; not every civilized person; but every person.
Note that this principle does not embrace bad behavior just that the bad behavior is not a result of being a bad person. That rogue cop, or despot, or exploitive capitalist is not a bad person, hesh has just embraced a bad belief system that leads them to ignore the first principle. If somehow one could change the belief system the inherent worth would emerge and the conscience (since this is OFS' thread) would repair the bad behavior.
Changing belief systems is an extremely difficult task. The brain builds blocks to information contrary to strongly held beliefs, so that contrary data is not even processed by the brain. Not impossible, Andrew Carnegie and Bill Gates come to mind as examples from the capitalist belief system. Possibly, it is early yet, but some have even attacked their own belief systems to bring them more in line with the First Principle, Pope Francis and Bishop Spong come to mind
In order to embrace the first principle it is necessary to be aware of and resist the brain's inherent tendency to create beliefs about other people. That is to generalize from behavior to the person. Currently, all Muslims are terrorists is a common belief that leads to terms like Islamist which reinforces the belief system to make it for practical purposes unassailable.
Even atheists can fall victim to beliefs based on belief systems: All Christians are bigots. Theists aren't reasonable.