This study about reviews and sales might seem to be conclusive evidence that reviews affect sales, but there are two reasons why it is not.

1. The participants were required to read the reviews, and most consumers are not.
2. The study asked those who intended to buy games, not those who did buy games.

Thus the study doesn't give an actual indication of whether reviews affect sales in real market conditions. The way to properly determine that might just require something along the lines of a Zogby or Gallup poll, asking people why they did or didn't buy certain games, and seeing what percentage of the answers were caused by reviews.

Of course such a study would be hugely expensive, as you'd need a decent sample size of people not only owning games, owning various systems, but, if you want to leave no doubt, also a number of buyers approximating the respective sales of the game. Even a getting the US President's approval rating wouldn't need to talk to that many people.

Another method would be to compare review scores and sales. Let me tell you, the film industry has known for years that reviews might as well be dart throwing. The disparity among box office and reviews scores is blatant there, but for some reason gaming hasn't caught on to this. Now perhaps with games there is a connection, but without verifying it, assuming a game did well/poorly because it got good/bad reviews is falling for the "correlation=causation" fallacy.

It's holding on to those assumptions without confirming them that lost Sony their first place, and made it all the harder, and more expensive, for Microsoft to get just to where they are.

Bump, since this needs to be discussed, rather than blindly assuming reviews affect sales in reality, when that survey only proved they affect sales in potentia.

I'm also sick of "this gote great/horrible reviews" as a justification to blame gamers for sales that go against the reviews.

I think a game needs good reviews to sale good, however just because it has good reviews, doesn't mean it'll selll good. This only applies to HD games.

Does apply just to them? Based on what?

the fact the Wii has many games will sup-par scores that sells pretty well.

Well, most of the best selling PS360 games have good scores (80 ). I'm too lazy to check if wii games do.

Well, it seems like highest selling games on HD consoles have good reviews, don't they? Give me some examples of HD console games with good sales and shitty(below 70?) reviews.

I think good reviews help sales, ultimately though it is the word of mouth that drives sales. Want a game to succeed tell everyone one you know how bad ass it is and slowly watch. Word of mouth is key, which means a game must be fun and sometimes the great reviewed games are not always that way for the majority of users. 

Hence why we have niche games with a rabid fan base but terrible sales.

Here is how I know reviews affect sales:

Because if a game gets shitty reviews, I don't buy it.

I'm ya huckleberry. That's just my game.

SOCOM: Confrontation scored in the 60s range and sold over a mil (1.01mil to be exact). Kane and Lynch also scored in 60s and sold around 1.3mil on both systems. Need 4 Speed Undercover also sold decent. Those are rare exceptions though.