Earlier quoted context omitted.
Assuming all other factors are almost identical, how would you want to prioritise amongst similarly qualified staff members?
By using a market? ie. allowing people to bid on slots directly. I know that the context for this is "non-economic proposals" so market based solutions doesn't count, but I'm not sure why you wouldn't want a market based proposal in this case.
I encourage you browse the web and see for your self, workplace psychology is an interesting study.