What does an 'I' rating indicate in USPSTF guidance?

• A. The balance of benefits and harms is certain.
• B. There is high certainty of net benefit.
• C. Evidence is insufficient to determine net benefit.
• D. The service is ineffective.

Answer: (C)

An I rating means there isn’t enough reliable evidence to determine the net benefit of the service. This happens when the available studies are sparse, inconsistent, of variable quality, or not generalizable, so researchers can’t confidently say whether the benefits outweigh harms (or vice versa). It doesn’t claim the service is effective or ineffective; it just flags uncertainty and the need for more research or careful, individualized decision-making. So the correct description is that evidence is insufficient to determine net benefit. The other statements imply certainty about benefit, certainty about no benefit, or inefficacy, which isn’t what the I rating represents.