All are true about incidence, except-

.<p>incidence rate is defin ed as the number of new case occurring in a defined population during a specified period of time.it will be seen from the above definition that incidence rate refers only to new cases,and during a given period usually assumed as one year.it also refers in a specified population or ";population at risk"unless other denominators are chosen.</p><p>ref:park&;s textbook of preventive and social medicine,22 nd edition,pg no 58</p>