“…Several modelling methods have been utilized to directly estimate the prevalence ratio when data have a cluster effect. Commonly used methods include log-binomial (log link) regression [ 33 , 34 , 35 ] and modified Poisson regression [ 36 , 37 ] with cluster-robust variance estimates (CRVE), log-binomial regression with Bayesian approach [ 38 , 39 ], mixed-effects regression models, and the marginal or population-averaged models using generalized estimating equations (GEE) with robust standard errors [ 29 , 40 , 41 , 42 , 43 ]. In all these methods, when data are clustered in more than one level, the most appropriate level must be chosen to estimate CRVE [ 44 ].…”