The phrase "high attrition" means that there is a large number of people leaving a group, organization, or company over a period of time. Full definition
Is it just to expand a charter school that achieves outstanding academic outcomes at the cost of high attrition rates? (justiceinschools.org)
Follow the link to read a piece by one of the school leaders written in response to news reports of high attrition rates. (myajc.com)
They have very low graduation rate, very bad test scores, very high attrition rates, and they'll have one teacher monitoring 100 screens. (prospect.org)