There are already many effective processes that have been developed, schools however don't want to implement them for varying reasons (blind marking for example).
An example from Daniel Kahneman's Noise (I'm paraphrasing) - When university faculty was told of their bias in marking from hunger/mood/normal daily human sways, why didn't the first person marking it write the grade on the back so the second couldn't see it until the end: They responded that they used to do it that way, but it caused arguments.
An example from Daniel Kahneman's Noise (I'm paraphrasing) - When university faculty was told of their bias in marking from hunger/mood/normal daily human sways, why didn't the first person marking it write the grade on the back so the second couldn't see it until the end: They responded that they used to do it that way, but it caused arguments.