Measuring the impact of drug resistance is an important step in understanding the scope of the problem and formulating policies to limit the emergence and spread of resistant organisms. Studies have focused on measuring the increased costs, morbidity, and mortality in patients with infections due to resistant versus susceptible organisms. These have generally found that resistance worsens outcomes. By focusing only on infected patients, however, they may understate the impact of resistance. It is important to recognize that resistance also affects the treatment of individuals with nonresistant organisms. In areas with high rates of resistance, physicians and governments have changed empiric therapy for malaria, tuberculosis, acute respiratory infections, and other diseases, increasing overall treatment costs. In some instances, these costs may exceed those attributable to treatment failure.