Hands up if you have ever followed your in-car sat nav down a dead end or followed the recipe to the letter but the dish is under/over cooked? I know I have.
What about your running GPS, heart rate monitor or business KPI dashboard? How do we know if the information they are giving us actually matches what we need and accounts for variability in human performance and other complex interactions?
Sometimes it pays to look through the windshield at the road you are heading down or check the food to see how much more cooking it needs.
It always pays to listen to your body when deciding how hard to train and often the best performance data a business can get is by listening to employees and customers.