Ah, yes. This does call for some explanation and no, sadly there isn't a secret formula to which only we are privy, which might have been more exciting than the actual answer.
Here's the story. For many a year, the act of being able to rate a venue was the exclusive preserve of LVA members. And, we must confess, the system in place was not very sophisticated, meaning you could rate something without letting us know who you were or why you'd picked the particular number you chose to award a buffet/hotel/attraction, etc.
For some reason, which only an unidentified member of our former IT staff who is thankfully now long-since departed could explain, the system was as complicated as it was unhelpful, with ratings calibrated in multi-fraction increments, weighting given to whether or not any venue was child-friendly (could a strip club be child-friendly and should it really be penalized for not being so?), and other such baffling anomalies.
So, as soon as we were able to, we put our heads together and re-thought the whole system. For one, we strongly felt that we should open up the privilege of rating to everyone, since the more feedback posted, the more useful it becomes to everyone, including us. We simplified it to consist of the standard 1-5 star system, increasing in half-star increments, just like amazon.com and other familiar sites.
We now insist that you put your username to your rating, both to help avoid someone with a grudge/agenda from ballot-stuffing and so that we can contact you if something doesn't quite make sense (a glowing review with a one-star rating, for example). We don't insist that you also leave a comment, although we strongly encourage you to do so. That way, others can see the motivation for your rating and judge for themselves whether you hated the show because it was lousy, or just that it wasn't your cup of tea and might be something they might love.
Another aspect of the old rating system was that no expiration dates were attached to anything. We all know how fast Las Vegas changes and that you can have a great meal at a restaurant on one trip, only to return the following year and be disappointed, then learn that the management has changed or the chef has moved on. However, we were aware that some good data on the site had been added under the old regime and we were loath to throw out the baby with the bathwater and eliminate all previous reviews/ratings. So, all we could do was take an arbitrary date -- we chose July 2007 -- and wipe out anything prior, while setting a new expiration date of 18 months for all ratings and reviews. It's not a perfect solution -- but then, when is anything in life? -- and, as time goes by, the system should "cleanse" itself, so that obsolete comments/ratings disappear off the radar.
This may well be the explanation for the discrepancies you found. Someone may have visited one of the hotels you'll be staying at a year or so ago and hated it, leaving no comment (you weren't obliged to back then), just giving it a lousy rating. That person may just have caught the joint on a bad day or it may since have been renovated and become much more agreeable to future reviewers, but is still being dragged down by a prior poor rating, which in due course will expire and stop skewing things.
And there's another reason why we urge everyone to rate and comment as much as possible -- from poker rooms to childcare, buffets to taxis, restaurants to strip clubs -- because when that critical mass is reached, the oddities are reduced and a much fairer and more useful picture emerges.
