# Any issue pooling single years (including 2020)? **URL:** \ **Category:** CPS\ **Created:** [September 14, 2021, 5:22pm UTC](https://forum.ipums.org/t/any-issue-pooling-single-years-including-2020/4312 "2021-09-14T17:22:21Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![sums031](https://sea1.discourse-cdn.com/flex019/user_avatar/forum.ipums.org/sums031/32/509_2.png) [@sums031](https://forum.ipums.org/u/sums031)\ **Post date:** [September 14, 2021, 5:22pm UTC](https://forum.ipums.org/t/any-issue-pooling-single-years-including-2020/4312/1 "2021-09-14T17:22:21Z")
Hello, I would like to combine CPS-ASEC, including 2020, into a multiple-year sample for a person-level analysis. Would that be an issue? If I can combine data across years including 2020, what weight should I use to analyze the data? PS: I saw a similar post but was unsure about including the 2020 sample. Thanks a lot! ---
**Author:** ![Matthew\_Bombyk](https://avatars.discourse-cdn.com/v4/letter/m/34f0e0/32.png) [@Matthew\_Bombyk](https://forum.ipums.org/u/Matthew_Bombyk)\ **Post date:** [September 17, 2021, 6:43pm UTC](https://forum.ipums.org/t/any-issue-pooling-single-years-including-2020/4312/2 "2021-09-17T18:43:30Z")
It is possible to include the 2020 ASEC in a multi-year sample, if the proper weights are applied. Because of the very unusual conditions of March 2020, the Census Bureau released a special set of weights just for the 2020 ASEC. These can be found in the variable [ASECWTCVD](https://cps.ipums.org/cps-action/variables/ASECWTCVD#description_section). The paper in the linked documentation describes the rationale for these weights and the procedure used to construct them. The proper way to incorporate these weights into a pooled sample would be to create a new weight variable, which takes the value of ASECWTCVD in 2020 and ASECWT in all other years. ---
**Author:** ![sums031](https://sea1.discourse-cdn.com/flex019/user_avatar/forum.ipums.org/sums031/32/509_2.png) [@sums031](https://forum.ipums.org/u/sums031)\ **Post date:** [September 17, 2021, 6:49pm UTC](https://forum.ipums.org/t/any-issue-pooling-single-years-including-2020/4312/3 "2021-09-17T18:49:49Z")
Thanks so much!