Is harmonized version of IND variable consistent?

I downloaded harmonized version of CPS starting from 1990 to 2020.
I can see the data consist of IND, IND1990, and IND1950.
If I use IND variable, is it consistently harmonized through 1990?
The explanation below in IPUMS webpage makes me confused.
스크린샷 2023-03-10 113026

No, the IND variable is not harmonized over this period. Each of the periods listed in your screenshot uses a different set of codes. The IND1990 and IND1950 variables are harmonized and generally consistent over time, although you should check out their comparability tabs (IND1990, IND1950) for more details. You can see which IND codes make up each code in IND1990 or IND1950 each year using the method described in this blog post.

Dear Matthew,

Thank you so much! It helps a lot

Jay Jeong.