The available data on | Delta B| = | Delta S| = 1 decays are in good agreement with the Standard Model when permitting subleading power corrections of about 15 at large hadronic recoil. Constraining new- physics effects in C7, C9, C10, the data still demand the same size of power corrections as in the StandardModel. In the presence of chirality- flipped operators, all but one of the power corrections reduce substantially. The Bayes factors are in favor of the Standard Model. Using new lattice inputs for B. K* form factors and under our minimal prior assumption for the power corrections, the favor shifts towardmodelswith chirality- flipped operators. We use the data to further constrain the hadronic form factors in B. K and B. K* transitions.