# Analysis Preparation Wizard: Estimation Method

This step allows you to specify an estimation method for the stage.

**WR (sampling with
replacement).** WR estimation does not include a correction
for sampling from a finite population (FPC) when estimating the variance
under the complex sampling design. You can choose to include or exclude
the FPC when estimating the variance under simple random sampling
(SRS).

Choosing not to include the FPC for SRS variance estimation is recommended when the analysis weights have been scaled so that they do not add up to the population size. The SRS variance estimate is used in computing statistics like the design effect. WR estimation can be specified only in the final stage of a design; the Wizard will not allow you to add another stage if you select WR estimation.

**Equal WOR (equal
probability sampling without replacement).** Equal WOR estimation
includes the finite population correction and assumes that units are
sampled with equal probability. Equal WOR can be specified in any
stage of a design.

**Unequal WOR (unequal
probability sampling without replacement).** In addition
to using the finite population correction, Unequal WOR accounts for
sampling units (usually clusters) selected with unequal probability.
This estimation method is available only in the first stage.