The students may differ but the material remains the same.They all still need to understand certain principles and be able to express certain competencies to proceed.Some students will still fall through the cracks unless they get special attention.They can be identified through regular assessments and either help given to them or at least concern raised to their parents.Making sure everyone knows the national and state ranking of schools will help enforce standards of quality in schools.Having state inspectors to go investigate poorly performing schools will help identify where the problem lies.
when i say competition, i mean that the whole society benefits from school competition.People will know which schools underperform.The horrible ones will improve.The top best schools will compete even harder while average shcools will strive and compete to enter the elite category of top performign schools.
One school i know gave cash incentive to teachers, which made some(on their own volition)come at odd hours to tutor kids.The math teachers even took students performing below a certain index number and gave them some remedial classes.Must it always include cash?? it does not have to but it does provides monetary returns in some way, in that the better a school is , the more students and the more money it gets.
Competition among students can encourage a better performance from kids and give them goals to work for.So as you can see competition is a multifaceted incentive that can be implemented in several ways.