Video review has been adopted across most major sports, yet no two systems resemble each other. The differences follow from the structure of each game rather than from disagreement about accuracy.
Natural stoppages decide what is possible
A sport that stops between every delivery or play can absorb a review without interrupting anything, because the game was already paused.
A continuously flowing game has no such gap, and stopping it to check an earlier incident freezes players and spectators in place.
Systems in flowing sports are therefore restricted to a narrow set of incidents, while stop-start sports can review far more without damaging the rhythm.
Factual questions are easier than judgements
Whether a ball crossed a line or a foot landed inside a boundary has a determinate answer that a camera can establish beyond argument.
Whether a challenge was reckless or a collision was avoidable is an assessment, and a second official watching a replay may simply reach a different view.
Sports that limit review to factual matters generate little controversy, while those that extend it to judgement calls import the original disagreement into a slower format.
Who may challenge changes everything
Some sports give each side a limited number of challenges, which makes the review a tactical resource that must be spent wisely.
Others place the decision entirely with officials, so incidents are checked automatically and teams have no ability to trigger a review at all.
The choice determines whether reviews cluster at critical moments, as they do when teams control them, or fall evenly across a match.
The threshold for overturning matters most
Most systems overturn an on-field decision only where the evidence is clear, leaving the original call standing where the footage is inconclusive.
That threshold is what makes two identical-looking incidents produce different outcomes, since the question is not what was right but whether the error was obvious.
Spectators reading the review as a search for the correct answer are consistently frustrated by a process designed only to correct plain mistakes.
Communication decides how it feels
Sports that broadcast the official's reasoning and show the footage in the venue keep the crowd inside the process while it happens.
Where the deliberation is silent and the crowd sees only a delay followed by a changed decision, the same accuracy produces far more resentment.
Much of the difference in how these systems are received is therefore about transparency during the pause rather than about the decisions they produce.