Not to pile on, but even if you disaggregated student loans on a per-individual basis, this graph would still be misleading because it does not include a line f

Not to pile on, but even if you disaggregated student loans on a per-individual basis, this graph would still be misleading because it does not include a line for the median wage of non-bachelor holders over the same period. In general, to know whether something is a good investment you must at least consider the next best alternative. Even this suggestion wouldn't be that great. To make a simple apples to apples comparison, we would need the graph of salaries of representative samples of comparable bachelors and non-bachelor holders. I don't really know what 'comparable' means in this context but it might be something like comparing the salaries of kids who graduated from college with kids who didn't go to college but could have (and maybe received comparable on the job training). One might also think that college affects, for instance, your likelihood of getting a job but we wouldn't want to get too complicated.