Does ipums provide the full data set for ACS one year surveys? or just a percentage of the responses?

I am attempting to replicate a study that uses ACS one-year datasets however my number of observations is far smaller than the study im attempting to replicate. Is this because IPUMS only gives a percentage of the full ACS data set?

IPUMS USA provides the full data set for the public use ACS files within each year. It could be that the study you are replicating is using the restricted use version of the ACS files. In this case, it could be that there are slightly fewer observations in the public use files compared to the restricted use files. Alternatively, if the number of observations are quite a bit different, then the origional study may be using the 5-year or 3-year pooled ACS files.