True morbidity in a population can be calculated by

Active Surveillance Extra measures are taken to collect data and confirm diagnoses to ensure more complete repos for surveys and outbreak investigations. Active surveillance encompasses formal and informal communications. Eg: Malaria surveillance by a health worker Main objectives of Surveillance 1. Provide information about new and changing trends in the health status of population - morbidity, moality, nutritional status 2. Provide feedback 3. Provide timely warning Ref: Park's Textbook of Preventive and Social Medicine; 24th edition - Page no. 45