The Doubters' Dilemma:Exploring student attrition and retention in university language and culture programs, by Mario Daniel Martín, Louise Jansen and Elizabeth Beckmann (August 2016) is available free on-line from ANU Press. While based on a study of student retention specifically in Language & Culture programs at the Australian National University (ANU), this work provides a useful analysis of the prob elms with measuring student retention in general and possible alternatives. It also argues that it is not just beginning students universities have to worry about retaining, but those in later years.
One issue which the study does not address is structuring programs to fit with student's working and family lives. A student who has to leave a three year degree program after six months, a year, or two years receives no degree. These students could be awarded a certificate, diploma or advanced diploma.