Information is a critical component of all public health activities. The purpose of public health informatics is to systematically apply “information and computer science and technology to public health practice, research, and learning.”1 The definition of public health informatics posited by O'Carroll et al. implies a broad range of activities drawn together by a focus on populations, not merely on individuals, and on public health organizations that operate with legal mandates. Although O'Carroll described informatics as primarily an engineering discipline, we believe that it is evolving more into a discipline of logical and strategic thought and management.
Medical and clinical informatics focus on improving the processes of diagnosis, care, and treatment of individuals. In contrast, public health informatics supports the activities, programs, and needs of those entrusted with assessing and assuring that the health status of whole populations is protected and improves over time. Public health informatics concerns itself with supporting programmatic needs of agencies, improving the quality of population-based information upon which public health policy is based, and expanding the range of disease prevention, health promotion, and health threat assessment capability extant in every locale throughout the world.
This chapter examines the historical and governmental context that guides the current evolution of the emerging public health informatics discipline, and describes some of the issues relating to the abilities of the public health worker to use information systems, as well as the larger scale issues relating to developing and implementing integrated information systems at regional and national levels.
John Snow conducted one of the first comprehensive epidemiological studies undertaken in response to the 1854 cholera outbreak in London. Snow investigated and mapped the locations of the homes of those who had died in the outbreak—one of the first geographic information applications in public health. By linking the locations of their homes to a single water pump on Broad Street in Soho, London, he established that cholera was a water-borne disease. Of the 89 people who died, only 10 lived closer to another pump. Within a week of the outbreak and armed with visual data, Snow convinced the authorities to remove the pump handle. Following that simple intervention, the number of infections and deaths fell rapidly.2
Over the past 30–50 years, public health programs have emerged around specific diseases (e.g., tuberculosis), behaviors (e.g., smoking), or technologies (e.g., immunization). Each of these new programs carried with it data and information needs and information systems were developed to meet these needs. Just as public health programs and their related information systems were evolving, so, too was technology. The technology changes associated with personal computing allowed for a more distributed approach to information system development. The conjunction of distributed computing and categorical public health programs led to a proliferation of information systems supporting narrowly focused public health programs—“silo” systems.