“…Sample size is easy to determine if a study only needs to draw geographic samples (Balch, Drapeau, Bowler, Booth, Goes et al 2004;Chen, Zhao, Gao, Henkelmann, and Schramm 2006;Conway 2006;Daly, Lei, Teixeira, Muir, Castillo et al 2007;Huang, Zhao, Shi, Yu, Zhao et al 2007;Valliant et al 2013b: Pearson et al 2015. However, it is not possible to know exactly how many persons are present in a randomly sampled geographic area before the area is selected (Landry et al 2005;Shannon et al 2012;Valliant et al 2013b;Chen et al 2015). One solution is to enumerate all households in a randomly sampled area after a geographic area is selected.…”