What is surveillance?
(go to Outline)
Surveillance is another data collection method with different strengths and weaknesses from surveys.
Systematic ongoing collection, collation, and analysis of data and the timely dissemination of information to those who need to know so that action can be taken.
-- World Health Organization
The ongoing systematic collection, analysis, and interpretation of health data, essential to the planning, implementation, and evaluation of public health practice, closely integrated with the timely dissemination of these data to those who need to know.
-- U.S. Centers for Disease Control and Prevention
But what does this mean?
Surveillance is the continuous gathering of health data needed to monitor the population's health status in order to provide or revise needed services.
Note the words "dissemination...to those who need to know" in both definitions. This means that collection of health data without sharing and using those data is NOT surveillance.
A little story:
When one of us asked the Ministry of Health staff if they had good communicable disease surveillance data, they proudly took him to a large closet, opened the door, and showed him stacks from floor to ceiling of yellow, moulding surveillance forms which had been completed and submitted to the Ministry over the past years. He asked if anyone had ever looked at these forms, and they acted very surprised at such a bizarre idea.
In sum, surveillance is data for action. If you don't plan to take any action, don't waste your time doing surveillance. If you need to take action, but need data to do so, consider surveillance as one of the data collection methods available.