Dear Michael,

Your code is correct. Not all surveys have the strata values stored in hv023, especially earlier surveys. For some surveys you need to construct the strata variable based on the stratification design used for that survey (usually by combining region and urban/rural place of residence). For some surveys the strata variable is stored in hv022 and not in hv023 and in some surveys the strata values are in both variables. For Gabon please use hv022 for the strata.

Thank you.

Shireen Assaf