Hi!
I am trying to replicate a table of the year of immigration of mexican migrants to the USA of 2023 using the the ACS 2023 from USCB (1 year estimates). I made the same table before with the ACS data from IPUMS (which you published in november 2024). The thing is that I dont obtain the same number of observations using the two sources. I used the equivalent variables (with IPUMS data I used the harmonized), filters and did all exactly the same, but the funny thing is that with IPUMS data I obtain more cases for the year of the ACS and 1 year before, for the previous year, so for example for before 1990 to 2021 I have the same cases, but for 2022 and 2023 they are different (by several hundreds in 2022 and by more or less ten thousand in 2023). I verified and repeated the process with the ACS data of 2022 and 2021 and it happens the exact same thing. I imagine it has to do with the harmonization of the variables and the method to recover cases without information, but I was hoping to confirm this with you 
I hope you can help me understand what is happening.
The variables I use are BPL (POBP in USCB ACS), YRIMMIG (YOEP). From what I have read, in the editing information of the variables, you recover missing information using other variables. So I think it can be that but the strange thing is that the number of cases is different only the year of the ACS and the year before (2023, and 2022 for example for the ACS 2023).
Thank you!
Thanks for your question. To look into this issue, I compared results from the Census Bureau’s Public Use Microdata Sample (PUMS) with the harmonized IPUMS USA version of these data. I did not see any differences between these two data sources. I describe my process for each below. I hope this is helpful in troubleshooting your analysis!
Here are the criteria I used for the IPUMS USA Online Analysis Tool. I chose to analyze the 2023 1-year ACS sample.
ROW: YRIMMIG
SELECTION FILTER(S): BPL(2000)
For estimates of the number of people in the US for each year of immigration, you will want to select “perwt”. For the unweighted sample size, you will want to select “None” for the weight. My unweighted case counts for persons in the 2023 1-year ACS who were born in Mexico (BPL = 200) are 2,241 who entered the US in 2022 and 1,509 who entered in 2023. When selecting “perwt”, the corresponding population estimates are 290,486 in 2022 and 179,684 in 2023, respectively.
To analyze the Census Bureau’s PUMS file, I used the MDAT tool. After selecting the 2023 ACS-1 Year Estimates PUMS, I added the variables POBP and YOEP. The first of these can go into the Columns field and the latter to Rows. I tabulated both unweighted counts and weighted estimates by selecting the corresponding option under Select Weight. The results were the same as those from the IPUMS USA analysis (see second screenshot below).
Though not directly related to your issue, you should be aware that ACS estimates of immigration in the survey year itself are systematically lower than the true number of arrivals. The continuous collection of data for the ACS throughout the year means that immigrants who arrive late in the year have a lower opportunity of being sampled. For example, while the 2023 ACS estimate of the number of immigrants from Mexico in 2022 was 290,486, this same estimate in the 2022 ACS was only 157,322.
IPUMS USA
Census Bureau MDAT
