For many pre-retirees who are short of their retirement goals, delaying retirement by a few years is the first solution they choose to building up their retirement income. But a new study by the Employee Benefit Research Institute (EBRI) finds that may not be as helpful as pre-retirees think.

According to the study, if boomers and Gen Xers delay their retirement past the age of 65, many of them still would not have adequate income to cover their basic retirement expenses and uninsured health care costs. In fact, even if a worker delays his or her retirement into their 80s, there is still a chance the household will be “at risk” of running out of money in retirement.

However, the chance of success for retirement adequacy improves significantly as individuals reach their late 70s and early 80s. A major factor that makes a difference in a person’s ability to meet their basic expenses and uninsured health care costs in retirement is the whether they are still participating in a defined-contribution retirement plan (such as a 401(k)) after the age of 65. Though percentage increases vary by several factors, defined contribution participation after 65 makes at least a 10 percentage point difference in the majority of the retirement age/income combinations.