LP v.s. surrender

I've had a lot of hopeless games where I end up wasting 20 minutes because someone on my team is convinced that surrendering a ranked match causes you to lose more LP. I used to think this was true, but my most reliable personal sources say it makes no difference. Since I haven't been playing as long as a lot of summoner out there, I know there's people with more experience in this later, so has anyone noticed some correlation between LP loss or gain and surrendering versus losing by Nexus death?