A priori indicates a judgment or conclusion reached without any basis in actual experience. Such judgments are considered to be ones where the truth is so self-evident that there is no point in obtaining actual evidence to support the conclusion reached. Thus, reasoning should be sufficient to arrive at a conclusion, without the need for physical evidence to bolster it. Another way of looking at the a priori concept is to arrive at a conclusion regarding a specific situation, based on a general concept or theory.
A priori decision making can be dangerous when used repeatedly, since the probability will rise over time that a "self evident" decision reached without any supporting experimentation is actually an incorrect decision. Errors are more likely to arise in complex decision environments.
Example of A Priori in Business
A company creates three budgets, which it designates as worst case, most likely, and best case. An a priori conclusion would be that, absent an experiment, the business is equally likely to experience all three scenarios, which means that you would assign a 33% probability to each one.
A priori is similar to deductive reasoning.