Imputation method for migration variables in CPS ASEC


I’m looking at the CPS ASEC migration-related variables. I have a few questions related to the imputation of missing values for these variables, and it would be great if you could help me with them!

  1. QMIGRAT1, the imputation flag for variable MIGRATE1, is only available after 1995. How were missing values treated before 1995? Were they discarded or allocated (if yes, any particular method)?
  2. QMIGRAT1 documents several categories of imputation methods. The allocation based on spouse makes sense to me. However, one of the method is “Migration status allocated from matrix mob”. Could you elaborate more on this method or point me to any description documents of these methods?
  3. Related to question 2, the imputation flag (QMIGST1B) for state of residence last year (MIGSTA1) also has several categories that involve “matrix” (see attached figure). Could you also talk more about these methods?

Thank you very much in advance!


Missing information in the CPS is filled in by enumerators using one of three general methods: relational edits (inferring the missing value from other characteristics on the person’s record or within the household), longitudinal edits (using data from previous months’ responses), and hot deck allocation (assigning a missing value from a record with similar characteristics). All of the methods that you find will fit into one of these three categories. However, I do not have knowledge of exactly how these methods have changed over the time period that the CPS has been administered. For more information, I recommend reaching out to the Census Bureau with your questions. I will attempt to answer your questions to the best of my ability below:

  1. The documentation does provide allocation flags for migration variables prior to 1995, but these have not been added to the IPUMS CPS database (see the 1994 codebook for allocation flags I-MIG1 & I-MIG4 on page 126). While the codebook provides different types of allocations when data on migration is missing (e.g. county and below assigned/allocated), details about the method are not provided.

  2. “Allocated from matrix mob” means that values from questions provided by the respondent were used to impute the MIGRATE1 value stated in the data set, as opposed to assigning the value based on the response of other household members.

  3. The 2020 ASEC codebook explains these allocation flags in the variable I-M5G2 (page 107). The “allocated from matrix” flags refer to allocation from answers provided by the respondent (as opposed to assigning values from other household members), with MIG1-MIG6 referring to different information provided by the respondent. Allocated from matrix MIG1 from instance refers to information provided by a respondent on their previous residence at geographic levels state and below, while Allocated from matrix MIG2 refers to information provided by a respondent on a foreign country that they previously lived in.

Thank you very much for the answers! This is helpful