# When is cpsid or cpsidp=0? I'm using data from 2000-2010 and there seems to be many each year with a value of 0. **URL:** \ **Category:** CPS\ **Created:** [December 5, 2017, 5:30pm UTC](https://forum.ipums.org/t/when-is-cpsid-or-cpsidp-0-im-using-data-from-2000-2010-and-there-seems-to-be-many-each-year-with-a-value-of-0/2057 "2017-12-05T17:30:00Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![deb.smu](https://avatars.discourse-cdn.com/v4/letter/d/7ba0ec/32.png) [@deb.smu](https://forum.ipums.org/u/deb.smu)\ **Post date:** [December 5, 2017, 5:30pm UTC](https://forum.ipums.org/t/when-is-cpsid-or-cpsidp-0-im-using-data-from-2000-2010-and-there-seems-to-be-many-each-year-with-a-value-of-0/2057/1 "2017-12-05T17:30:00Z")
I’m using data from 2000-2010. I need to create a panel, so I need to use the cpsidp to link individuals over time. However, many of the observations each year seems to have a value of 0. Why is this the case? ---
**Author:** ![tfliao](https://avatars.discourse-cdn.com/v4/letter/t/5f9b8f/32.png) [@tfliao](https://forum.ipums.org/u/tfliao)\ **Post date:** [December 5, 2017, 6:58pm UTC](https://forum.ipums.org/t/when-is-cpsid-or-cpsidp-0-im-using-data-from-2000-2010-and-there-seems-to-be-many-each-year-with-a-value-of-0/2057/2 "2017-12-05T18:58:00Z")
I don’t really have an answer but I have a related question. I’ve recently downloaded the 2013 March CPS and the ATUS WB data, with the intention to link the two datasets. I used the Stata code provided to import the data. However, I’ve found a large number of cpsidp=0, over 72k, in the CPS data but not in the WB module. Without a proper cisidp, there’s no way one can merge the two datasets. ---
**Author:** ![JeffBloem](https://sea1.discourse-cdn.com/flex019/user_avatar/forum.ipums.org/jeffbloem/32/40_2.png) [@JeffBloem](https://forum.ipums.org/u/JeffBloem)\ **Post date:** [December 5, 2017, 7:35pm UTC](https://forum.ipums.org/t/when-is-cpsid-or-cpsidp-0-im-using-data-from-2000-2010-and-there-seems-to-be-many-each-year-with-a-value-of-0/2057/3 "2017-12-05T19:35:00Z")
The answer to both of these questions is that CPS respondents who are part of the ASEC oversample ([ASECOVERP](https://cps.ipums.org/cps-action/variables/ASECOVERP#codes_section)) have CPSIDP values of 0. This is essentially because, at the present time, it is only possible to link ASEC respondents who are also part of the March basic sample to other basic monthly samples. More information about these details can be [found here](https://cps.ipums.org/cps/resources/linking/4.workingpaper16.pdf). ---
**Author:** ![tfliao](https://avatars.discourse-cdn.com/v4/letter/t/5f9b8f/32.png) [@tfliao](https://forum.ipums.org/u/tfliao)\ **Post date:** [December 5, 2017, 9:15pm UTC](https://forum.ipums.org/t/when-is-cpsid-or-cpsidp-0-im-using-data-from-2000-2010-and-there-seems-to-be-many-each-year-with-a-value-of-0/2057/4 "2017-12-05T21:15:00Z")
Thank you for answering the question so promptly. Your answer seem to suggest that those in the ASEC supplement don’t have a cpsidp, or did you mean only those who appear both in the supplement AND in the regular CPS who don’t have a cpsidp? My further test seems to suggest the latter. Of the 87,652 cases in my analysis of the March ASEC, 28,766 had cpsidp=0. Once these are dropped, I was able to proceed with the merge with the WB module, resulting in a “small” merged dataset of 1,909 cases. Also, thanks for the linked working paper, which I’ll read more carefully. The paper suggests that CPS surveys are longitudinal. Along those lines, what proportion of the March ASEC supplements are carried over from year to year? Any idea? Many thanks. ---
**Author:** ![JeffBloem](https://sea1.discourse-cdn.com/flex019/user_avatar/forum.ipums.org/jeffbloem/32/40_2.png) [@JeffBloem](https://forum.ipums.org/u/JeffBloem)\ **Post date:** [December 6, 2017, 2:54pm UTC](https://forum.ipums.org/t/when-is-cpsid-or-cpsidp-0-im-using-data-from-2000-2010-and-there-seems-to-be-many-each-year-with-a-value-of-0/2057/5 "2017-12-06T14:54:00Z")
I’ll try to clarify in more detal. Linking the ASEC with basic monthly samples requires two steps. First, linking the ASEC to the March basic sample. Second, linking the March basic sample to other basic samples. Note that the ASEC sample includes individuals not only from the March basic sample, but also from other month’s basic samples. This linking process implies that it is only possible (at the present time) to link individuals from the ASEC who are also members of the March basic sample. Therefore, individuals who are part of the ASEC oversample (e.g. in the ASEC but not in the March basic sample) have CPSIDP values of 0. The working paper linked above also explains this detail. ---
**Author:** ![tfliao](https://avatars.discourse-cdn.com/v4/letter/t/5f9b8f/32.png) [@tfliao](https://forum.ipums.org/u/tfliao)\ **Post date:** [December 6, 2017, 4:01pm UTC](https://forum.ipums.org/t/when-is-cpsid-or-cpsidp-0-im-using-data-from-2000-2010-and-there-seems-to-be-many-each-year-with-a-value-of-0/2057/6 "2017-12-06T16:01:00Z")
Thanks, Jeff, for the clarification, which confirms what I suspected to be the reason. All the best, Tim ---
**Author:** ![Kelly\_Jones](https://avatars.discourse-cdn.com/v4/letter/k/f6c823/32.png) [@Kelly\_Jones](https://forum.ipums.org/u/Kelly_Jones)\ **Post date:** [June 24, 2020, 11:53pm UTC](https://forum.ipums.org/t/when-is-cpsid-or-cpsidp-0-im-using-data-from-2000-2010-and-there-seems-to-be-many-each-year-with-a-value-of-0/2057/7 "2020-06-24T23:53:19Z")
On a related note. I am not using ASEC but only the June fertility supplement data. Why are there individuals with cpsidp==0? ---
**Author:** ![KariWilliams](https://avatars.discourse-cdn.com/v4/letter/k/82dd89/32.png) [@KariWilliams](https://forum.ipums.org/u/KariWilliams)\ **Post date:** [June 26, 2020, 10:12pm UTC](https://forum.ipums.org/t/when-is-cpsid-or-cpsidp-0-im-using-data-from-2000-2010-and-there-seems-to-be-many-each-year-with-a-value-of-0/2057/8 "2020-06-26T22:12:03Z")
The only cases where CPSIDP is equal to 0 in the fertility supplement data are children under the age of 14 in 1979-1981. Children under 14 are only included in data files for October supplements in 1976 and 1977, and all months containing supplement data in 1978-1981. It is _theoretically_ possible to link these children _if_ the months of entry to the survey and timing of supplements falls correctly. However, given the highly specific requirements for timing to link these children, IPUMS CPS does not recommend it and has assigned CPSIDP values of 0. ---
**Author:** ![MEHLIKA\_OZSOY](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@MEHLIKA\_OZSOY](https://forum.ipums.org/u/MEHLIKA_OZSOY)\ **Post date:** [February 14, 2021, 10:55pm UTC](https://forum.ipums.org/t/when-is-cpsid-or-cpsidp-0-im-using-data-from-2000-2010-and-there-seems-to-be-many-each-year-with-a-value-of-0/2057/9 "2021-02-14T22:55:49Z")
Hi, now that I look the data after 2010s, I see some HHs have both cpsid (NOT equal to 0) and also has 10 digit marbasecidh. I am confused since if marbasecidh refers only to the common HHs in ASEC and Basic monthly and if those are the ones with cpsid=0 as it mentioned above, then why do I see some observations that have cpisd NOT equal to 0 but 14 digit number? Regards ---
**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:** [February 19, 2021, 4:01pm UTC](https://forum.ipums.org/t/when-is-cpsid-or-cpsidp-0-im-using-data-from-2000-2010-and-there-seems-to-be-many-each-year-with-a-value-of-0/2057/10 "2021-02-19T16:01:46Z")
The households with CPSID = 0 are those that cannot be linked between ASEC and the March Basic CPS, because they are in the ASEC oversample. This is indicated in the variable [ASECOVERH](https://cps.ipums.org/cps-action/variables/ASECOVERH#codes_section). All linkable households have a 14-digit CPSID (NOT EQUAL TO 0). Both CPSID and MARBASECIDH are used for linking households in the CPS. The main difference is that MARBASECIDH only links households between ASEC and March Basic samples, while CPSID is used to link households across months, for example to link the same household’s surveys in April and May. CPSID also links households between ASEC and March Basic samples, so MARBASECIDH is not necessary if you are using CPSID. ---
**Author:** ![MEHLIKA\_OZSOY](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@MEHLIKA\_OZSOY](https://forum.ipums.org/u/MEHLIKA_OZSOY)\ **Post date:** [February 19, 2021, 4:10pm UTC](https://forum.ipums.org/t/when-is-cpsid-or-cpsidp-0-im-using-data-from-2000-2010-and-there-seems-to-be-many-each-year-with-a-value-of-0/2057/11 "2021-02-19T16:10:42Z")
Ok thank your for the explanation. I really appreciate it.