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The Peru Continuous DHS, and I believe the Senegal Continuous DHS are representative each year (indeed in Peru, each semester). In order to combine surveys, the weights need to be denormalized. Traditionally DHS "normalizes" sampling weights by dividing each weight by the sum of the original sampling weights and multiplying by the total number. either interviewed households or interviewed persons, depending on whether it is household data or individual data. This normalization process

is unnecessary and creates problems in combining surveys. To denormalize the weights is simple, just multiply each weight in a given survey by the inverse of the normalization factor, i.e. by the the sum of the original weights divided by total number of cases. The problem is obtaining the sum of the original cases, which can be gotten by looking at the standard recode programs for that survey or tabulating the original weights.

Another issue is the wealth index, since it is usually based on each survey year. Use the Comparative Wealth Index instead.

One has to beware about changes in the sampling frame as well, such as when a new frame is based on a new census since the population distribution and definitions of rural and urban and states may have changed between the frames.]]>