The term ‘firm but fair’ has two components. First, it suggests that if a child or a student, (in the case of a parent or an educator), is not acting appropriately, then a firm consequence is put in place. The second part is that the consequence is fair. This means that the consequence is fitting, rather than either soft or overly harsh, and it also means there is consistency in what the consequences look like for similar instances.
The often overlooked aspect of this is that fairness needs to be measured by the person who is receiving the consequence. It should be ‘firm but fair’ in their eyes. If you think you are being fair but the person dealing with the consequence does not, then that mismatch will undermine the value of the consequence, and likely not deter the kind of behaviour you are hoping to reduce.
For a parent, this can often be an issue where anger levels can undermine consistency, where the consequence is unfairly harsher because your kid was driving you crazy for an hour before the issue came up, compared to a less harsh consequence just because you are in a good mood. For an educator, this issue can often come up when consequences are not consistent between different students for similar issues.
An important concept to remember is that if you are wanting to be fair, fairness needs to be perceived by everyone involved. In whose eyes are you being firm but fair?