topic Re: Unexpected number of cases as result of a concatenation operation. in Discussions

Unexpected number of cases as result of a concatenation operation.

LNitz — Tue, 18 Aug 2026 02:49:35 GMT

I have extracted from 2025 and 2024 Census SIPP files the records for householders in the month of December. There are 13910 records in 2025 and 15,877 in 2024. I am using the Catenate command to link the two files, not a merge or update command. I am creating a new file with a column indicating source.

I get a file of 15,877 records, not 33000. I get no source column. Since these records were collected in different years, the same person's record would not be the same over two years, because year is one of the data elements.

It seems that concatenation is simply not occurring. Any thoughts?

Re: Unexpected number of cases as result of a concatenation operation.

jthi — Tue, 18 Aug 2026 12:03:37 GMT

Concatenate is fairly simple platform and I don't remember concatenate platform having issues of not doing anything. Are you sure Concatenate platform is the one you are using?

Some questions:

Which JMP version are you using?
In which format is the data coming in?
Are any errors being printed to log?
Anything being captured after you run the concatenate in the enhanced log?
Do tables have identical columns (datatypes, column names)?
Can you replicate the same issue with any other datasets?
Are there any table scripts/table variables in your tables?

Re: Unexpected number of cases as result of a concatenation operation.

Thierry_S — Tue, 18 Aug 2026 16:36:38 GMT

Hi,

To add to @jthi, it is more common to end up with a concatenated table with too many columns when the column names in the first file do not exactly match those in the second file.

To confirm the steps you are using:

Open both tables
Go to the 2024 table
In the Tables menu (top ribbon), select Concatenate
In the menu, select your 2025 table (left-most pull-down menu)
Select/deselect the options for "Create Source Column", "Save and Evaluate Formulas", and "Append to first table"
Click OK

You should get, at a minimum, a table with all the rows from the 2024 and 2025 tables.

If you are using a different approach, let us know so we can assist more precisely.

Best regards,