In the United States, there are 50 state court systems plus the District of Columbia and federal court systems (not including territories such as American Samoa, Guam, the Northern Mariana Islands, Puerto Rico, and the U.S Virgin Islands). Court hierarchies in each jurisdiction follow this established pattern:
Highest appellate court
Intermediate appellate court (if one exists)
The holdings of cases decided by the highest-level appellate court in a jurisdiction are mandatory precedent for the lower courts in that particular hierarchy.
The holdings of cases decided by intermediate appellate courts are not binding on courts at the higher appellate level. They are less likely than decisions of the highest court to carry persuasive weight in other jurisdictions.
Cases decided at the trial level which are not appealed usually generate no written opinion, are not reported, and are not considered precedent.
Court decisions are good law (that is, they can be relied upon) unless they are reversed by a higher appellate court, they are overruled by the same court, or a statute renders the holding obsolete.