1210.1 Assessment
Research Question (Clear, unambiguous) "Does a high level of student debt hinder a graduate’s ability to advance socio-economically?"  Without further specification, the meaning of this research question is unclear.  Obviously, if all else is equal, a graduate with high debt is worse off that one with no debt, and if their career development is exactly the same, the one with debt would be behind until the debt was erased and any residual effects of that debt (such as reduced savings) dissipated.  We do not need research to figure this out.  So, what beyond this is the research question?
Relevant Literature The titles of the three listed articles seem relevant, but just listing titles tells us little.
Causal Interpretations (clear, all parts defined, mechanisms, controls, plausible) "Sociol-economic mobility after graduation" is obscure.  Presumably, the intent is a reference to income or occupational status attainment over time.  No actual discussion of causal mechanisms or possibilities appears here.  The one "alternative" cause mentioned is irrelevant - of course, the field of degree and status of the college credential will influence achievement opportunities, but on the surface this is independent of the implications of debt.
Data (variables, sample, comparison) The data do not seem to make sense for the question.  The '87 data are too old to reveal anything about current student debt under different economic and legal conditions.  The GSS could only have value if it has information about student debt - does it?
Research Value The reasons offered seem vague and at the level that it is generally good to know what makes life harder.  Presumably, we already know that debt does this.
Overall This project seems fairly offhand and not well developed.