The doctrine of judicial precedent means that judges can refer back to previous decisions to help decide similar cases where the law and facts are alike. This doctrine is concerned with the influence and value of past decisions of case law and the judge's prior legal experience.
For the doctrine of judicial precedent to work, a hierarchy of courts is needed. Judges must refer to a higher-ranking court and follow the same line of reasoning of one of its previous cases in order to appeal to a precedent. The concept is based on stare decisis, which is used when one stands by what has been decided. In this usage of precedent, like cases should be treated alike for the sake of certainty and consistency. The usage of the doctrine is supposed to promote fairness and predictability.
There are some ways in which judges may avoid precedent, including distinguishing. This technique is used when a judge determines that the facts presented in the case at hand differ enough from the previous case, and could lawfully alter the outcome. The facts used for differentiating between the two cases must be relevant and sufficient, as minor details may not be enough to merit a distinction between the two cases.