# Replicating ATUS weighted estimates with AHTUS

Hi all

I have a question about calculating population-level estimates of total participants in activities in AHTUS to replicate estimates using ATUS. Using infltwt divided by 365 days I obtain numbers that are relatively plausible but they are below the weighted estimates using ATUS. Why is that the case? See below an example:

Using ATUS:

svyset caseid [pw=wt06]
svy: mean sex if year==2018

Population size estimate = 95,591,791,615, which divided by 365 results in about 262 million people.

Using AHTUS:

svyset ident [pw=infltwt]
svy: mean sex if year==2018

Population size estimate = 63,931,201,658, which divided by 365 results in about 172 million people.

See detailed output below. I’m puzzled by this discrepancy. Shouldn’t the two estimates be the same? Which one is correct?

Thanks!

Pilar

OUTPUT using ATUS

. svy: mean sex if year==2018
(running mean on estimation sample)

Survey: Mean estimation

Number of strata = 1 Number of obs = 9,593
Number of PSUs = 9,593 Population size = 95,591,791,615
Design df = 9,592

``````     |             Linearized
|       Mean   std. err.     [95% conf. interval]
``````

-------------±-----------------------------------------------
sex | 1.515828 .0070061 1.502095 1.529562

OUTPUT using AHTUS
. svy: mean sex if sample==2018
(running mean on estimation sample)

Survey: Mean estimation

Number of strata = 1 Number of obs = 9,593
Number of PSUs = 9,593 Population size = 63,931,201,658
Design df = 9,592

``````     |             Linearized
|       Mean   std. err.     [95% conf. interval]
``````

-------------±-----------------------------------------------
sex | 1.51914 .0061262 1.507132 1.531149

We’ve already corresponded about this by email, but I wanted to post a follow-up here for reference for other IPUMS users. We really appreciate you bringing this issue to our attention as it helps improve data on IPUMS for all users. After reviewing the data and discovering the source of this inconsistency, IPUMS Time Use derived corrected weights for RECWGHT, INFLTWT, and XTIMEWT in the 2018 American Time Use Survey in the AHTUS. These were released on 1/18/23. We recommend anyone who used the previous weights to re-run their analysis with the corrected weights. Please reach out to us through this post or at ipums@umn.edu with any further questions on this issue.