发病率(attack rate,incidence)这一专用名词,是医学统计学中经常使用的一个频率概念。它具有自己特定的含义。发病率是反映人群在某一期间(年、季、月)内某疾病新发病例频度的指标。一般以某地区或某人群一年内发生的某病新病例数与该地区同期平均人口数之比来表示。计算公式为: Attack rate (incidence) is a term used frequently in medical statistics as a frequency concept. It has its own specific meaning. Incidence rate is a reflection of the crowd in a certain period (year, quarter, month) an indicator of the frequency of new cases of disease. It is usually expressed as the ratio of the number of new cases of a disease occurring in a region or a population within one year to the average population of the same period in the region. The formula is: