Everyone has biases that affect their decisions either for the good or the bad.
Understanding that we have biases emphasizes the need for a strong decision-making process. To have an effective decision-making process you need to understand the outcome of the decision and how your biases affect your evaluation of the outcome.
A good decision process consists of evaluation criteria with a weighting. The evaluation criteria is further grouped into major groupings.
Every option is given a score for each criterion. The score is multiplied by the weighting for the criteria. The total is then calculated for each option. The option with the highest total is the winning decision.
The quality of the decision can then be analyzed based on the quality of the evaluation criteria used. Your biases may cause you to think an option is a good decision, but the quantified scoring may dictate otherwise. Your biases will show up in the weightings (which indicate how important a criterion is) but you now have the numbers to evaluate if that bias is justified or not.