Can someone pease me summarize this sentence asap

private schools by definition operate independently—they are not a common good. as a result, they’re generally not subject to rules holding them accountable for a certain level of student performance. no rules mean no agreed-upon measures, which mean no standardized assessments whose results parents and policymakers can consult. in other words, in an all-private-school world, there wouldn’t be an apples-to-apples way of judging the quality of individual institutions, which could have wildly different curricula and expectations.