I did a search on the forum I did not find it, my suggestion is what the title says, give say a 5% speed boost to research speed per secret lab level constructed up to a maximum of 30% total research speed boost.
So if you have a lvl5 and a lvl1 or two lvl3 you achieve the max 30% research speed boost.
Cheers
So if you have a lvl5 and a lvl1 or two lvl3 you achieve the max 30% research speed boost.
Cheers