I am planning to come to the US for a period of 5 weeks to conduct independent research as visiting scholar in a University. I will not receive any payment, and travel and accomodation expenditures will be covered by my home university (outside US). Is it sufficient the VWP or do I need another kind of visa? During the interview if the CBP ask me which kind of business I am going to undertake, is it sufficient to answer "independent research"? thanks a lot!
The Visa Waiver Program permits the same activities as a B visitor visa (B1 or B2).
The sort of short term independent research you propose is covered under B1 status and is explicitly listed as an example of a permitted activity by the US Embassy Japan (and likely many other places).