# Missing CPSIDP in ASEC?

**URL:** <https://forum.ipums.org/t/missing-cpsidp-in-asec/5925>\
**Category:** CPS\
**Created:** [June 5, 2024, 4:37pm UTC](https://forum.ipums.org/t/missing-cpsidp-in-asec/5925 "2024-06-05T16:37:13Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Yun\_Taek\_Oh](https://avatars.discourse-cdn.com/v4/letter/y/9dc877/32.png) [@Yun\_Taek\_Oh](https://forum.ipums.org/u/Yun_Taek_Oh)\
**Post date:** [June 5, 2024, 4:37pm UTC](https://forum.ipums.org/t/missing-cpsidp-in-asec/5925/1 "2024-06-05T16:37:13Z")

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Hello!! I am trying to link two consecutive ASEC files using CPSIDP. I found that many respondents have missing CPSIDP (= 0). These people also have missing CPSID and CPSIDV.

Are there any other identifiers that allow me to link the same people in two consecutive ASECs? It seems like MARBASECIDP existed before but not anymore?

Thanks,

Yun taek

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**Author:** ![Ivan\_Strahof](https://sea1.discourse-cdn.com/flex019/user_avatar/forum.ipums.org/ivan_strahof/32/626_2.png) [@Ivan\_Strahof](https://forum.ipums.org/u/Ivan_Strahof)\
**Post date:** [June 7, 2024, 8:24pm UTC](https://forum.ipums.org/t/missing-cpsidp-in-asec/5925/2 "2024-06-07T20:24:59Z")

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Hi Yun Taek,

The CPS ASEC supplement contains respondents who completed the CPS March Basic Survey as well as oversample respondents drawn from samples from previous months. [CPSIDP](https://cps.ipums.org/cps-action/variables/cpsidp#description_section) = 0 refers to these CPS ASEC oversample respondents ([ASECOVERP](https://cps.ipums.org/cps-action/variables/ASECOVERP)). IPUMS CPS does not currently link respondents of the oversample to their Basic Monthly CPS interview. As a result, these repondents do not have CPSIDP (person level linking key), [CPSID](https://cps.ipums.org/cps-action/variables/CPSID) (household level linking key), or [CPSIDV](https://cps.ipums.org/cps-action/variables/CPSIDV) (validated person-level linking key) values. [MARBASECIDP](https://cps.ipums.org/cps-action/variables/MARBASECIDP#description_section) is a unique identifier for linking respondents in the March Basic to their response to the ASEC supplement. However, since ASEC oversample respondents did not complete the March Basic survey, there is no response to link to. Please see [our technical write-up](https://cps.ipums.org/cps/resources/linking/marbasecid_FloodS_pdf_version.pdf) for more information on this issue as well as [Pacas & Rodgers, 2023](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10805443/) for more information on linking ASEC oversample respondents.

IPUMS CPS users can request longitudinal ASEC samples directly from [the](https://cps.ipums.org/cps-action/samples)_[Select Samples](https://cps.ipums.org/cps-action/samples)_ page (select _Longitudinal, 1 year apart_). These samples automatically exclude individuals who belong to the ASEC oversample. More information about these linked samples can be found in [the longitudinal sample notes](https://cps.ipums.org/cps/longitudinal_asec_notes.shtml).