The document discusses measuring the incidence of tuberculosis (TB) in a community for planning and evaluation purposes. It defines incidence as the number of new and recurrent cases of TB occurring in a given year. It also distinguishes between recurrent and relapsed TB cases and defines pulmonary and extrapulmonary TB, with pulmonary TB involving the lung parenchyma or tracheobronchial tree, while extrapulmonary TB involves any confirmed TB case in organs other than the lungs such as the pleura, lymph nodes, or bone.