Which statement about NNT is correct?

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Multiple Choice

Which statement about NNT is correct?

NNT expresses how many patients, on average, must be treated to prevent one adverse outcome within a specified time. It is the reciprocal of the absolute risk reduction (ARR), where ARR is the decrease in event rate due to the treatment (ARR = control event rate minus treated event rate). So, NNT = 1 / ARR. For instance, if a treatment lowers risk from 20% to 12%, ARR = 0.08, and NNT = 1 / 0.08 = 12.5 (about 13 people). NNT depends on the time frame and the baseline risk, so it can change across studies. This statement directly captures what NNT measures. The other ideas either describe the magnitude of risk reduction itself or refer to screening or duration, which are not what NNT conveys.

NNT expresses how many patients, on average, must be treated to prevent one adverse outcome within a specified time. It is the reciprocal of the absolute risk reduction (ARR), where ARR is the decrease in event rate due to the treatment (ARR = control event rate minus treated event rate). So, NNT = 1 / ARR. For instance, if a treatment lowers risk from 20% to 12%, ARR = 0.08, and NNT = 1 / 0.08 = 12.5 (about 13 people). NNT depends on the time frame and the baseline risk, so it can change across studies. This statement directly captures what NNT measures. The other ideas either describe the magnitude of risk reduction itself or refer to screening or duration, which are not what NNT conveys.

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