Tests are calibrated on their false positive (alpha) and false negative rates (beta). If you have a lot of financial/upside/pain information then you can start to determine the relative pain of each of those kinds of failures and calibrate accordingly. At the end of the day the best choice is some complex function of the cost of false positives, the cost of false negatives, the cost of each new observation (which is probably non-linear), the upside of a discovery, and the prior likelihood of finding a discovery.
Which is to say you can definitely pick better choices for alpha, but it's really hard so everyone just picks whatever their field agrees is "OK". In science it's often 95%.
Which is to say you can definitely pick better choices for alpha, but it's really hard so everyone just picks whatever their field agrees is "OK". In science it's often 95%.