HANOVER, N.H. — NOW that it’s clear that Obamacare is here to stay, its supporters should focus on making the program better. Fixes are not a sign of weakness. They are a sign of responsiveness and of good management. And the Affordable Care Act does have its flaws. Here’s a big one: It favors screening over diagnosis.

While the distinction may seem arcane, it has real-world implications. Screening is what we offer to the well; it’s the effort to find abnormalities in those who do not have signs or symptoms of disease. Because screening is considered part of preventive care under the Affordable Care Act, it is provided at no charge.

Diagnosis is what we offer to those who do have signs or symptoms of disease. Because diagnosis is not preventive care, it is subject to deductibles and co-payments.

In other words: A woman over 40 can have a free screening mammogram. But if she notices a breast lump and goes to her doctor to have it evaluated, she’ll pay for a diagnostic mammogram. That could cost $300. So the woman at lower risk for cancer — the one with no signs or symptoms of the disease — has an incentive to be tested, while the woman at higher risk — the one with the lump — faces a disincentive.