Does a reduction in the discretion of the public buyer through strict regulatory and procedural control make it possible to reduce corruption and increase the efficiency of public procurement? Using a multitasking agency model, we analyze the interactions between integrity concerns and the performance objective in public procurement. We show that the effect of coercive measures on the behavior of the procurer is counterintuitive. The model explains that the extrinsic formal incentives (control, sanction) are likely to produce effects far from those sought not only by reducing the effort to the performance of the buyer but especially by not acting against the corruption. These findings challenge some beliefs about the effectiveness of rigid rules and procedures in fighting corruption and improving public procurement performance.