Three researchers from Iowa State University have used the data from the National Longitudinal Survey of Youth 1997 for a quantitative analysis of the correlation between parental divorce and parental educational expectations for their children and the graduate success: enrolment and completion of graduate studies: Parental Divorce, Social Capital, and Postbaccalaurate Educational Attainment Among Young Adults.
They tested the hypotheses that children from divorced parents (by now 40% of the age group) would have lower rates of graduate success and that this would at least in part be caused by lower parental expectations. They found, however, that divorced parents had no lower educational expectations for their children on post baccalaureate education – but that these divorcees children indeed have a 29% lower chance of completing a graduate degree (for the Bachelor’s the effect is even stronger: 44%). The study doesn’t claim to give the final answer on the impact of parental divorce on graduate attainment, or on the explanation for that impact. As they say; more work is needed.