Methods and systems for determining usage are described. Initially, site-centric data and panel-centric data are accessed and pre-processed. Initial usage measurement data is determined based on the pre-processed site-centric data. One or more adjustment factors are determined based on the pre-processed panel-centric data. The one or more adjustment factors are applied to the initial usage measurement data to generate an adjusted usage measurement data. Reports based on the adjusted usage measurement data are generated.