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All other units were given a chance of coming into the sample based on the
FTE employment and total payroll of the unit. Prior to selecting the sample,
the file was ordered by state; within state, by type of government; and within
type of government by population for cities, counties, and townships and by
enrollment for school districts. For special districts, the file was ordered
by probability of selection within function code.
Prior to mail-out, analysts update the sample universe file with births (units
that did not exist during prior years of the survey) that have come into existence
since the prior year processing cycle. All city, county, township, and school
district births are added to the sample with a probability of selection of 1.
Special district births are sampled at a rate of 1 in 25.
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Weighting:
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The weight for each unit in the sample is the inverse of that unit’s probability of
being selected into the sample. For example, for units that were included in the
sample with a probability of .02, the weight is (1/.02)=50. For units that were
included in the sample with a probability of 1, the weight is 1.
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Sample size:
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The sample size is around 11,000 units. Of the total number of governments in the sample,
approximately 13% are counties, 23% are cities, 14% are townships, 30% are special districts,
and 19% are school districts. All 50 state governments and the District of Columbia are
certainty units with a weight of 1.
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