Basketball group tables are separated by point difference rather than by results alone. That makes the margin of a win a competitive objective in itself, sometimes long after the outcome is decided.
Why margin is used at all
Group stages are short, so several teams frequently finish level on wins. A tiebreak has to distinguish them using information already generated by the matches played.
Basketball produces a continuous score rather than a handful of goals, so margin is a reasonably granular measure of superiority.
Sports with low scoring cannot rely on it as heavily, which is why football places head-to-head results and goal difference in a different order.
The mini-league principle
Most competitions first compare only the matches between the tied teams, forming a mini-league of those results before considering the wider group.
Within that mini-league, wins are counted first and point difference second, and only then does the calculation widen to include all group matches.
The restriction matters because a team that lost heavily to a weak opponent should not be rescued by a large win over another weak opponent.
What this does during a match
A team certain of victory may continue pressing for points, which appears unsporting but is a rational response to a published tiebreak.
Conversely, a losing side has an incentive to reduce the deficit even when the result is settled, so late garbage-time possessions carry real weight.
Coaches calculate the required margin in advance and communicate it to players, particularly in final group matches where the permutations are known.
The awkward cases
Three-way ties are the difficult ones, because removing one team from the calculation can change the order of the remaining two.
Regulations therefore specify that the mini-league is recomputed after each elimination, which occasionally produces counterintuitive results.
Because the process is mechanical, it is defensible even when the outcome surprises, which is the main virtue of a published tiebreak sequence.
Why the alternative is worse
Replaying tied matches is impossible within a tournament calendar, and drawing lots is unpopular because it discards information the matches produced.
Point difference at least reflects what happened on court, even if it weights a blowout against a weak opponent more heavily than the record deserves.
The system accepts a known distortion in exchange for a result that can be calculated immediately and explained without judgement.
