A recent paper investigated veterans of Iraq and Afghanistan to find out how much they were claiming in VA disability benefits. The answer is: a lot.
The study primarily looks at male soldiers who joined up between 2001 and 2011 and were assigned to a brigade combat team. What the chart above shows is that general disability payments didn't go up. This includes SSI, SSDI, and workers compensation. However, VA disability payments skyrocketed.
Why? Excellent question, and one that the authors ended up unable to answer. They controlled for a vast number of variables (age, race, IQ, number of years deployed, etc. etc.) and it turned out that these predicted exactly nothing:
Outcomes were measured eight years after enlistment, so 2009 through 2019. None of the things they thought might predict disability payments did so after the first few years. By the 2011 cohort, they explained literally zero.
So again, why have VA disability payments skyrocketed? The authors first suggest it's because we've passed a bunch of laws that make it easier to claim benefits. They back this up with a long list of changes to the law. But still, why would later cohorts take advantage of these laws more than earlier cohorts? I'm not sure this explains much either.
In fact, it turns out the whole thing is even more mysterious than it seems:
The results show that deployments have become less dangerous over time and simultaneously generated larger increases in VADC receipt.... The causal effect of a 10-month deployment on VADC compensation more than doubled during this period.... SSI/SSDI, by contrast, shows a very different pattern. The effect of a 10 month deployment on total payments from these programs decreased from $490 to $145 over the same period, consistent with the declining combat risk.
Disability payments from general programs decreased, as you'd expect from soldiers who were less exposed to combat later in the wars. But VA benefits surged.
Why why why? The final attempt to explain this is something else entirely: declining standards for new recruits.
Changes in deployment and exposure to violence across cohorts effectively explain none of the changes.... Observable selection, however, is a far better predictor of changes in noncombat deaths.... As more soldiers with lower AFQT scores and more moral waivers enlisted in the mid-2000s, noncombat deaths increased.
Hmmm. Noncombat deaths rise for a few years partly as a result of lower recruiting standards (and other things), but by 2010 it's showing zero effect. Did recruiting standards really change that much in two years? And even if this is real, the effect is smallish and only for noncombat deaths. It doesn't seem to account for anything else.
In the end, the authors suggest that greater generosity in awarding disability benefits, along with changes in the quality of the soldiers, can explain some of the huge increase in VA disability benefits. But even by their own account, not very much of it. The whole thing remains a mystery.
POSTSCRIPT: If I had to guess, I'd say disability benefits have risen largely because later cohorts were far more aware of the benefits available to them, and far less squeamish about claiming them. But the study didn't look at that, so it's only a guess.