ADP data does have a bias, but it is so much data it provides a valuable signal. The importance of understanding the source of your data and how it represents the largest population is something every scientist has been drilled on.

> over 900,000 small businesses trust ADP [0]

From what I can find they have 1.1m clients and over 900k are small businesses. The vast majority. This makes sense, as there aren’t that many massive companies.

[0] https://www.adp.com/what-we-offer/payroll/payroll-for-1-49-e...

two small companies i used to work for used adp.

...You know that "startup" is not synonymous with "small company", right?

What's the situation in the vast swath of the economy that's made up of small non-startup companies?