For those new to these concepts, performance monitoring involves the selection of specific demographic or health factors that can be measured and that relate meaningfully to whatever health outcome is sought. For this text on the health of communities, the factors range from characteristics of a community (such as age, race, poverty, unemployment, death rates, child abuse, smoking, money spent on health care, health status) to very specific conditions of concern to a particular community (such as vaccine-preventable diseases, depression, violence, breast cancer, and cervical cancer). Performance measurement is based on the assumption that we can define what is important to our health, measure it, report it, compare it, and use these data to improve our health.