INDEPTH membership is given to institutions that run health and demographic surveillance systems (HDSSs). These are the parent institutions which we refer to as member centres of INDEPTH. A director of such a centre or his/her designee is referred to by INDEPTH as a centre leader. However, some centres have two or more HDSS field sites. Each of these HDSSs may have heads (field station managers, for example). INDEPTH considers these heads as Site Leaders. ALL centre/site leaders receive communications from the Resource & Training Centre.