WHY PUBLIC HEALTH SURVEILLANCE? From: Patel MS. Service-Oriented Training in Public Health. A model for Enhancing Public Health Surveillance in the Pacific. A Report to the Secretariat of the Pacific Community & the Pacific Public Health Surveillance Network, Oct 1998.  Link to the complete report in PDF (156 KB)
Every country needs the capacity to measure and analyse continuously the health status of its population. It does so through public health surveillance. Public health surveillance is defined as the ongoing and systematic collection, collation, analysis and interpretation of health data, and the communication of the information derived from these data to those responsible for disease prevention and control. The communication aims to stimulate responses to health problems, and to use the information for planning, implementing and evaluating programs and policies for disease prevention and control. To be useful, the information must be timely, particularly for the purpose of communicable disease surveillance and control (see figure 1). Figure 1- The Surveillance Wheel Surveillance is therefore a tool for assessing and monitoring the health status of the population. It tells us where health problems are, who is affected, and where prevention and control activities should be directed. It helps us to define priorities for health programs and policies, and also to monitor and evaluate the effectiveness of public health interventions. Health care providers are familiar with the model of providing clinical care to an individual seeking medical attention, in terms of the diagnostic and therapeutic components of clinical practice. The concept of surveillance in public health may be explained in analogous terms. An important difference is that while individuals will seek medical attention for an illness, it is the public health system that has to design ways for identifying problems deserving attention in the community. Just as clinical practitioners use symptoms and signs to diagnose and treat the individual patient, public health practitioners use surveillance to assess and respond to the health needs of the community (Table 1). Table 1 - The use of surveillance by public health practitioners and the analogy with the way clinical practitioners use symptoms and signs | CLINICAL PRACTITIONERS USE SYMPTOMS AND SIGNS | PUBLIC HEALTH PRACTITIONERS USE SURVEILLANCE DATA | | to assess the health status of the patient | to assess the health status of the community | | to diagnose the nature and severity of illness | to diagnose the nature and extent of adverse health events and exposures in the community, e.g. morbidity and mortality, nutrition, lifestyle factors | | to assess whether further investigations (eg. Laboratory tests, X-rays) are needed | to assess whether further epidemiological investigations (e.g. community surveys, case control or cohort studies) are needed | | to confirm the diagnosis or to explore the problem further | to confirm or explore the problem further | | to determine whether treatment is indicated | to determine whether public health interventions are indicated | | to evaluate response to treatment | to evaluate response to interventions |
A clinical service needs practitioners competent in clinical practice. Practitioners should be able to integrate and synthesise information provided by the patient and other sources (e.g. laboratory scientists, radiographers, dietitians, physiotherapists) to diagnose the problem, and to develop plans for treatment and evaluating treatment. Without a competent clinical practitioner, the quality of assessment of the patient's health and treatment is likely to be deficient or even harmful. Similarly, a public health service needs practitioners competent in the practice of surveillance. These practitioners should be able to integrate and synthesise data from multiple sources (e.g. health care providers, death registries, demographers, health information systems, nutritionists, health educators, health promoters) and to transform them into public health actions, programs and policies. Without practitioners skilled in managing a system of public health surveillance, the quality of assessment of a population's health status will be deficient or misleading, and the resultant public health responses may even be harmful. In the absence of valid surveillance data, the allocation of scarce and dwindling health resources will be more likely to be driven by other vested interests, and not primarily by the needs of the community. Surveillance is therefore not simply the collection and reporting of health data. It is a system that collects and synthesises data from diverse sources in the community and health sector, and helps to set, and to guide progress towards achieving, national health goals and targets. | Back to the top | Back to the Background page | Link to the achievements pages | ____________________________________________________________ | 
