reciprocal of difference number needed to treat COKA/SEVCO Brian S. Alper, Harold Lehmann, Joanne Dehnbostel, Kenneth Wilkins, Janice Tufte Expert Working Group Agreement: 2022-07-20 vote 7-0 by Cauê Monaco, Janice Tufte, Philippe Rocca-Serra, Mario Tristan, Jesus Lopez-Alcalde, Harold Lehmann, Eric Harvey NTTB A statistic that represents the number of units that needs to be treated to prevent one additional undesired outcome. The Number Needed to Treat is calculated as the reciprocal of a treatment effect estimate, where the effect estimate is expressed as a risk difference. The Number Needed to Treat (NNT) value is often rounded up to the next highest whole integer number needed to treat to benefit NTT requires discussion