A good choice at work does one of three things. It saves money, it earns money, or it makes things better for people. If it does none of them, why bother?
When you're deciding whether something is worth doing, ask which of three goals it helps with. Saving money, making money, or looking after people. The goal tells you what to measure afterwards.
Tie each decision to a primary goal (cost avoided, revenue gained, or people outcomes such as workload, safety and fairness) and a measure. Decisions with no goal get dropped. Decisions with conflicting goals get the trade-off written down.
Save money
Most decision improvements start here because the numbers are easiest to find. A faster approval saves staff time. A better renewal decision stops paying for licences nobody uses. Measure the time or spend before and after, and count only what actually stops.
Watch for savings that just move cost elsewhere. If a model approves invoices faster but a person spends an hour a week correcting its mistakes, count that hour.
Make money
Some decisions earn money: which leads to chase, which bids to submit, what price to quote. These are harder to measure because the counterfactual is invisible. You don't see the deal you would have won. Use a comparison group where you can, or track the hit rate over enough decisions to see a trend.
Look after people
This goal covers workload, fairness, safety and the experience of the people affected by a decision. A rota decision that cuts overtime, or a triage rule that stops urgent cases sitting in a queue, may save little money and still be the most valuable change you make.
Measure it directly. Count the overtime hours, the wait times, the complaints. Ask the people involved.
When goals conflict
Sometimes saving money means more work for someone. Write the trade-off down in the decision record: what you gain, what it costs, and who bears the cost. A trade-off that's written down can be revisited. One that isn't tends to get forgotten until it becomes a complaint.