Fairness Isn’t Equal Minutes

The real problem

Players arrive late. Someone gets injured. A goalkeeper plays under different constraints. A coach needs to respond to what is happening on the field. Substitutions happen at imperfect moments. Some players have already played significantly more or less by the time anyone notices.

The problem is not that coaches do not care about fairness. The problem is that fairness is a moving target inside a system that is already demanding their attention.

Most coaches are managing several things simultaneously: watching the game, communicating with players, thinking about positions, dealing with injuries, responding to parents and making substitutions without disrupting the team.

The result is often not deliberate unfairness. It is accumulated approximation. A player stays on for another five minutes because the coach is distracted. Another sits through two consecutive rotations. The substitution plan made before the game stops matching what actually happened.

What existing approaches get wrong

One response is to make the system extremely rigid: calculate exactly equal playing time, produce a substitution timetable and follow it regardless of what happens during the game.

Mathematically, that is appealing. Operationally, it can fail. Sport is not a spreadsheet. A substitution may need to happen early. A player may need to stay on. A team may suddenly have fewer available players. The plan has to survive contact with the actual game.

The opposite approach is to abandon structure altogether and rely on memory. That preserves flexibility, but it also recreates the original problem. Neither extreme is particularly useful.

The principle guiding Smart Sub Saver

Make fairness visible, then leave the human in control.

Smart Sub Saver is not designed to determine who deserves to play. It is designed to help a coach understand what has happened, what is likely to happen next and where playing-time differences are developing.

For some teams, fairness may mean getting everyone as close as practical to equal playing time. For another team, it may mean managing breaks more consistently. For another, there may be specific positional or developmental considerations.

Software can help organise those constraints. It should not hide them. A good tool should reduce cognitive load without pretending that the underlying judgement has disappeared.

What Ex Parvis is testing

We are testing whether substitution planning can become both more precise and easier to understand. The important part is not simply generating a mathematically correct rotation. The important part is whether the rotation remains useful to a coach standing beside a field with twenty other things happening.

• Track actual playing time rather than relying only on a pre-match plan.
• Identify players moving ahead of or behind their intended time.
• Adjust future rotations when the game changes.
• Give coaches different levels of control over how tightly playing time is balanced.
• Make the reasoning behind a proposed rotation understandable.
• Preserve manual control when the coach wants to override the plan.

What remains uncertain

There is no universal definition of fairness in sport. Equal minutes can be appropriate in one context and inappropriate in another. A development team, representative team and social competition may reasonably operate differently.

Even within one team, a coach may need to balance participation, positions, player wellbeing and the competitive situation. We do not think software should flatten those differences into a single definition.

A mathematically perfect solution may require substitutions so frequently that the game becomes worse for everyone involved. That would solve the numerical problem while creating a human one. Finding the useful point between precision and practicality is part of what we are still testing.