How does skill-based matchmaking work, and why is it controversial?
Skill-based matchmaking (SBMM) places players in matches against opponents of similar ability, using a hidden rating derived from performance.
How the rating works. Most systems descend from Elo or its successors — Glicko, which adds a confidence measure, and TrueSkill, developed by Microsoft specifically for multiplayer and team games.
The basic logic: each player has a rating and an uncertainty. Beating a higher-rated opponent gains more than beating a lower-rated one. As more games are played, uncertainty falls and the rating moves less. Team games must additionally infer individual contribution from a shared outcome, which is genuinely difficult.
What matchmaking actually optimises. Not purely fairness. Systems balance several objectives simultaneously:
Match quality — an even contest.
Queue time — nobody waits five minutes.
Connection quality — geographic proximity for low latency.
Team balance and party sizes.
These conflict. Tighter skill matching means longer queues and worse connections, and every game chooses a point on that trade-off.
Why it is controversial in casual modes:
Every match feels like work. If the system always finds opponents at your exact level, you win roughly half your games regardless of improvement, and matches are consistently intense. Players describe casual play feeling sweaty and never relaxing.
Improvement is invisible. Getting better produces harder opponents rather than easier wins, so the feeling of progress disappears.
It removes the variety of occasionally dominating and occasionally being outclassed, which some argue was part of the appeal.
Suspicion of engagement optimisation. Patents exist describing matchmaking that manipulates outcomes to drive purchases or retention, which has fuelled distrust — though patents describe possibilities rather than proving deployment.
Opacity. Most games do not disclose whether SBMM is present or how strong it is, and publishers rarely confirm details.
The counterargument: without it, new players are repeatedly destroyed by veterans and quit, which kills a game faster.