It is often a tough question:  Mom has an illness that could be treated with surgery. The operation is routine for a younger patient. But is it too risky for an elder like mom?

Today, doctors who consider the special risks of surgery for older patients must use complicated and time-consuming assessments to judge whether an operation is the best choice. But University of Colorado (Denver) surgeon Thomas N. Robinson has found a highly-reliable and incredibly simple test: Ask the patient to stand up, walk 10 feet, and sit down.

If she can do it in 10 seconds or less, post-surgical complications are likely to be low and the chances of her living more than a year relatively high. If she takes 15 seconds or more, odds are she’ll suffer complications from the surgery. And the chances of her dying within a year rise dramatically.  The American College of Surgeons journal  Surgery News published a more detailed account of the study last month.

The effort to better predict outcomes before heading into the operating room is only one piece of a broader effort to rethink surgery for older patients. Other steps include developing special surgical techniques and better understanding the goals of older patients and their families.

Robinson found that a patient’s ability to stand up, walk a few paces, and sit down (called a TUG test for timed up-and-go) is a great way to measure frailty. For example, only 3 percent of fast walkers in his experiment had some form of dementia while 92 percent of slow walkers were cognitively impaired. Just 7 percent of fast walkers had fallen within the past six months, but 85 percent of slow walkers had taken a tumble.

The test is also valuable because it directly measures leg strength, which is important because patients recovering from surgery do best when they can get up and walk.

As a result, Robinson’s test gets roughly the same results as much more complicated assessments. For instance, the Veterans Administration uses a 24-variable tool to measure surgery risk for its patients. The American College of Surgeons developed its own complex outcomes database called the National Surgical Quality Improvement Program (NSQIP).

But surgeons often don’t bother using these tools because they take too much time and often include lots of data the surgeons think are extraneous. Thus, their default choice is often to do the surgery even when the risk is high and the outcome uncertain.

Robinson’s tool shows how much riskier surgery is for frail patients who struggle to walk that 10 feet. For those in his study who had cardiac surgery, 11 percent with a fast time in the TUG test had post-op complications while more than half of those with a slow time developed complications. Only 2 percent of fast walkers died within a year compared to 12 percent of slow walkers.

For those who had colorectal surgery, the results were even more dramatic. The complication rate was 12 percent for the fast walkers but 77 percent for the slow walkers. Chances of dying within a year went from 3 percent to 31 percent.

These decisions are never easy, but would you want surgery if you had a 3 in 4 chance of developing an infection or other complications and a 1-in-3 chance of dying within a year? Or would you explore other options?

A reliable and easy test is only the first step, of course. Surgeons—who are notoriously resistant to change–still have to use it. If they don’t, patients and their families should ask. And then doctors and their patients have to do something equally important. They all need to talk honestly about the risks of surgery and its alternatives, including palliative care.