# Replicate Weights Margin of Error

**URL:** <https://forum.ipums.org/t/replicate-weights-margin-of-error/3760>\
**Category:** USA\
**Created:** [September 17, 2020, 7:36pm UTC](https://forum.ipums.org/t/replicate-weights-margin-of-error/3760 "2020-09-17T19:36:16Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Matthew\_Hutton](https://avatars.discourse-cdn.com/v4/letter/m/51bf81/32.png) [@Matthew\_Hutton](https://forum.ipums.org/u/Matthew_Hutton)\
**Post date:** [September 17, 2020, 7:36pm UTC](https://forum.ipums.org/t/replicate-weights-margin-of-error/3760/1 "2020-09-17T19:36:16Z")

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Hi,

I am curious about the sample error outputs from the microdata replicate weights vs those supplied by the official data tables on [data.gov](http://data.gov). I have done a quick tabulation by sex in Philadelphia County. While the estimates are roughly equal to what is showing on [data.gov](http://data.gov), the margins of error are much larger.

I calculated the margin of error with a 90% confidence interval, as suggested by the Census Bureau.

Is this variance between the microdata sample and the official tabulations typical? Are the official margins of error calculated with a different method?

 ![image](https://us1.discourse-cdn.com/flex019/uploads/ipums/original/1X/91d075003ff910b91614e1e2f5e7bbab46034708.png)

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**Author:** ![KariWilliams](https://avatars.discourse-cdn.com/v4/letter/k/82dd89/32.png) [@KariWilliams](https://forum.ipums.org/u/KariWilliams)\
**Post date:** [September 24, 2020, 1:16pm UTC](https://forum.ipums.org/t/replicate-weights-margin-of-error/3760/2 "2020-09-24T13:16:36Z")

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I am not sure exactly which tables you are using from [data.gov](http://data.gov/), but would direct you to the most recent [ACS data user’s guide](https://www.census.gov/content/dam/Census/library/publications/2018/acs/acs_general_handbook_2018.pdf) for more information on margins of error for tabular data from the Census Bureau. In general, I would expect to see wider confidence intervals using the PUMS microdata than aggregated estimates, though I am surprised at how small the margins of error are in the official estimates you shared. For what it’s worth, I replicated your point estimates and margins of error for a 90% confidence interval using the ACS 2018 5-year data.