Courts in one jurisdiction are influenced by decisions in others, and notably better rules may be adopted over time. McNamara and I.
The continued attraction of the National Reporter Service citations for cases published in its pages and of Westlaw and Lexis citations for 'unpublished' cases loaded in their services is uniformity across courts.
As the subsequent judicial process unfolds the parties and presiding judge continue to exchange documents with one another - motions, responses, memoranda of law, orders, decisions, and judgments.
In practice, the need for predictability means that lower courts generally defer to the precedent of higher courts.
The ratio is used to justify a court decision on the basis of previous case law as well as to make it easier to use the decision as a precedent for future cases. Thus common law systems are adopting one of the approaches long common in civil law jurisdictions.
For any state judicial branch progressing toward greater levels of state funding this was an attractive target.