Stratified Sampling

Stratified random sampling intends to guarantee that the sample represents specific subgroups or strata.



  • This sampling method ensures adequate representation of all subgroups
  • When there is homogeneity within strata  and heterogeheity between strata, the estimates can be as precise (or even more precise) as with the use of simple random sampling


  • Requires the knowledge of strata membership a priori
  • Adds complexity to the analysis plan