When are Research Agreement modifiers activated?

[lovepack]

I was curious if you need The Porcelain tower BEFORE you made the agreement to get the bonus or if you could build it the turn before a research agreement ended and still receive the the full benefit. The same goes for rationalism finisher. Thank you for taking the time to read this and answer.

lovepack

 

[Browd]

As long as you get PT and/or Scientific Revolution before the RA ends, you will get the associated RA yield boost.

 

[lovepack]

Thanks