The most common assumptions of what causes a worker to retire early are valid, but they may play a smaller role than many suspect. A study by the Center for Retirement Research used the Health and Retirement Study (HRS)—an ongoing study of older adults—to identify what role health, employment, family or finances played in causing a worker to retire earlier than planned.

Approximately 40% of those experiencing a health shock retire early. It’s often not the initial change in health, but rather a further deterioration in health. The study’s authors say “each additional health condition a person has at their planning age is associated with a 3.3-percentage-point increase in the probability of early retirement.” If health was not a factor in planning and workers experienced no health shocks, then early retirement would fall by slightly less than five percentage points, from 37.0% to 32.2%.

Having an older parent move in has an impact. If the parent requires care, it can be very difficult for the parent’s son or daughter to both devote time to their parent and maintain employment. Less than 2% of the sample had a parent move in with them, however.

A more influential familial change is having a spouse retire. When one spouse retires early, workers are 4.2 percentage points more likely to retire early themselves. The study’s authors estimate that if both spouses retire at the same time, 36.2% of individuals would retire early.

Layoffs can lead to early retirement. A person who is unable or unwilling to find a new, suitable job may simply opt to retire. Involuntary job loss has a small impact on actual rates. If no workers were laid off or otherwise lose their jobs (as opposed to voluntarily leaving them), the reduction in early retirement would be just 1.9 percentage points.

If health, familial changes, job loss and even changes in financial wealth are removed, 27.1% of workers would still retire early (versus the actual 37.0%). Put another way, more than a quarter of workers retire early for other reasons. The study’s authors say this points to “idiosyncratic, hard-to-measure factors” that may have a greater influence.

Source: “What Causes Workers to Retire Before They Plan,” Alicia Munnell, Geoffrey Sanzenbacher, and Matthew Rutledge, Center for Retirement Research at Boston College, September 2015.