What's the diff between ACS and 1% sample in year 2000? Is ACS 2016 & 1% 2000 sample comparable as both are 1/100.

Comparing ACS 2016 characteristics to 1% sample in 2000.

The sample descriptions page should provide the information to address these questions. Specifically, the 2000 ACS sample is approximately a 1-in-750 random sample and the 1% 2000 sample is a 1-in-100 random sample. The 2016 ACS sample, on the other hand, is a 1-in-100 random sample. As this points out, the ACS surveys follow a slightly different sampling framework in years before 2005.

Additionally, the 1% sample is drawn from the decennial census while the ACS is entirely separate from the decennial census.