Win rates of 1/2BB live dont translate to 3-6BB online, why?

[mntbikr15]

So a friend of mine brought this up and in truth I had never thought about(mainly due to limited live play experience) and dont really know the answer.

He said that good players have seen fairly consitent win rates of 1-2BB/100 playing live. His question to me was why doesnt that same player make 3-6BB/100 online. I think he was basing this on the fact that 30-40 live hands is 1/3 the 100-120 hands that are played per hr online(hes talking shorthand games here).

The first thought that came to my mind was regarding true win rates and sample sizes. I dont want to turn this into a debate for what sample size is needed, but Ive heard anywhere from 100-500k for exposing "true" winrates. Playing 30-40 hands an hr at only one table I dont imagine many players have that kind of sample for live play, which could affect results.

Another possibility was differance in games, but from my limited live play experience I dont think the difference, if any, would be enough to drastically affect win rates per 100 hands.

The final thought that I had pertained to ability to read players/body language better, but again I didnt think it would cause such drastic differences.

Any other thoughts/theories on this? If its been discussed before Im sry, I searched and didnt find anything of much help.

Thanks in advance,
Evan

PS- I suppose the final thought I had was that he was misinformed of live win rates, but havent looked into that side of it yet.