For example an equitable approach to criminal prosecution is that people are exonerated or convicted based on the best available evidence, with no variance attributable to their ability to afford a lawyer (an equitable approach enshrined in our Constitution but still a challenge for society).
And an equitable approach of salary is that people are paid in proportion to their contributions to the business, with no variance attributable to the color of their skin (for example).
We have to measure inputs and outcomes to infer the state of equity because we don’t have a reliable deterministic model of society.