One of the lesser-known offspring of the Patient Protection and Affordable Care Act has come under fire for its "sluggish" performance in measuring the effectiveness of health care treatments.

The Patient-Centered Outcomes Research Institute was created by the health care reform law to gauge the effectiveness and appropriateness of health care treatments. It's doing so through what's called comparative effectiveness research, which helps researchers determine whether, for example, spinal fusion surgery works better than the alternatives in relieving back pain, or whether proton beam therapy is worth the extra cost to treat prostate cancer.

These are questions that private industry and federal agencies have largely steered clear of. Even the federal Food and Drug Administration, although it judges whether treatments are safe and effective, has avoided comparing whether treatment A is more effective than treatment B.