"To base a decision" means to make a choice or judgment based on certain facts, information, or evidence that supports it. It involves using important factors or reasons as a foundation for reaching a conclusion. Full definition
Knowing your daily calorie and nutrient intake will help you make data based decisions on changes that you need to make to your diet. (build-muscle-and-burn-fat.com)
We want evidence based decision making in our government. (slaw.ca)
«I can't base my decision on what other people are doing,» he said. (newsday.com)