In the system that the ACCP has adopted, the strength of any recommendation depends on the following two factors: the tradeoff between the benefits and the risks and burdens; and the quality of the evidence regarding treatment effect. We grade the tradeoff between the benefits, and the risks and burdens into the following two categories; category 1, in which the tradeoff is clear enough that most patients, despite differences in values, would make the same choice, leading to a strong recommendation; and category 2, in which the tradeoff is less clear, and individual patient values will likely lead to different choices, leading to a weak recommendation. We grade methodological quality in terms of the following three categories: randomized trials that show consistent results, or observational studies with very strong treatment effects; randomized trials with limitations, or observational studies with exceptional strengths; and observational studies without exceptional strengths and case series. The framework summarized in Table 2 generates recommendations from the very strong (benefit/risk tradeoff unequivocal, high-quality evidence, grade 1A) to the very weak (benefit/risk questionable, low-quality evidence, grade 2C). Whatever the grade of the recommendation, clinicians must use their judgment, considering both local and individual patient circumstances, and patient values, in making individual decisions. In general, however, they should place progressively greater weight on expert recommendations as they move from grade 2C to grade 1A.