When you have a medical decision to make, you want to make the right one. What most people don’t realize is that medicine is highly individual. There may not be a “right” decision—only a decision that’s right for you.

Bottom Line/Personal asked Jerome Groopman, MD, and Pamela Hartzband, MD, who wrote Your Medical Mind: How to Decide What Is Right for You, what you need to consider when making a medical decision…

Determine whether you’re a maximalist or minimalist. Some patients (and doctors) believe that the most treatment is the best treatment. Dr. Groopman tends to be one of them. For example, many years ago, he underwent a spinal fusion because he was convinced that medical science could identify the cause of his back pain and fix it. (It was a mistake—he has suffered from severe back pain ever since and is now somewhat less of a maximalist.)

Dr. Hartzband is a medical minimalist. She never rushes to have tests or procedures. She errs on the side of avoiding medical care until she is convinced that she needs it.

Both approaches are valid as long as you are willing to adjust your thinking as you go along. A maximalist needs to remind himself/herself that it’s sometimes better to slow down, to think twice before agreeing to a particular treatment. A minimalist needs to keep in mind that it is sometimes better to see a doctor today rather than next week or to have a test that he/she would rather avoid.

Run the numbers. Statistics can help you make a decision. Let’s use an example to show what we mean. More than 30 million Americans take statin drugs to reduce cholesterol. These medications can prevent heart attacks in some people, but they also can cause side effects, mainly muscle pain (myopathy). You can use numbers to help you decide whether to take them. Consider the following…

What’s the risk without treatment? Suppose that you’re a woman in her 40s who generally is healthy. Your only risk factor for heart disease is high cholesterol. Your risk of having a heart attack if you don’t take a statin is about one in 100 over 10 years.

You might decide that your heart attack risk is so low that it’s not worth taking medication. Or you might conclude that any increase in heart disease risk is unacceptable regardless of the possible side effects.

Statistical framing. Numbers can be presented in either a positive or negative way. How you frame statistics can change your thinking.

Example: Statins cause muscle pain in between 1% and 10% of patients. That sounds like a high risk, and some people might refuse medication because of it. But you might feel differently if you reframe the numbers. The number of people who don’t get side effects is between 90 and 99 out of 100. That’s more reassuring. You need to look at the numbers in both a positive and negative way to get a balanced view.

Use a health calculator. The US Department of Health and Human Services, along with other health agencies, offers online calculators to help you understand the risks and benefits of medical decisions. (Find calculators at www.HealthFinder.gov.) You fill in basic information, such as your age, health history and lifestyle habits. Then you click a button to give you a general idea of how likely you are to, say, have a heart attack or a stroke in the next 10 years. This can help you decide how aggressive you want to be about different treatments.

Balance alternative therapy and conventional therapy. About 60% of Americans use some form of alternative therapy—herbs, nutritional supplements, etc. They believe that the body, given the right support, usually can maintain and heal itself. Others put more faith in drugs and cutting-edge technologies.

Best: Don’t blindly follow either approach. Some conditions—such as an infection or a ruptured appendix—must be treated conventionally. Alternative approaches, including lifestyle changes, can be helpful for self-limiting conditions (such as a cold) or certain kinds of chronic diseases such as some forms of arthritis, which often can be only partly managed with conventional treatments.

Don’t let anecdotes overinfluence you. The stories that we hear can powerfully affect our decisions. Psychologists call this “availability bias.” When you hear that someone had terrible side effects from chemotherapy, you might refuse to try it yourself even if you need it. Or you might insist on having a particular treatment because someone you know had good results from it.

Every patient is different. The stories you hear might not reflect a larger reality.

Know the guidelines—but don’t insist on them. Committees of specialists have developed “best practice” guidelines for treating different conditions. Patients may believe that their doctors always should follow these guidelines.

Not true. Guidelines are useful because they incorporate a lot of information about treatment options. But they’re less scientific than you might think. Committee members have their own biases…the studies they base decisions on have limitations…and researchers may have ties to drug or device manufacturers—a worrisome conflict of interest.

Also, guidelines change rapidly. One study that looked at 100 recommendations from expert committees found that 14% were reversed within one year…23% within two years…and half were overturned after more than five years.

Gather opinions. There are many gray areas in medicine. Different doctors will recommend different approaches, each with risks and benefits. It’s always a good idea to get a second—and sometimes even a third—opinion before having a major procedure or if there’s any doubt about the diagnosis. The final decision will be yours, but the information you collect can guide your thinking.

Sources: Jerome Groopman, MD, the Dina and Raphael Recanati professor of medicine at Harvard Medical School and chief of experimental medicine at Beth Israel Deaconess Medical Center, and Pamela Hartzband, MD, assistant professor of medicine at Harvard Medical School and an endocrinologist at Beth Israel Deaconess Medical Center. Based in Boston, they are coauthors of Your Medical Mind: How to Decide What Is Right for You (Penguin). www.YourMedicalMind.com