To calculate the overall star rating and percentage breakdown by star, we do not use a simple average. Instead, our system considers things like how recent a review is and if the reviewer bought the item on Amazon. It also analyses reviews to verify trustworthiness.
This backpack carrier is a fine size for a kitten -- ours is currently 7 lbs -- but our 12.5 lb adult cat barely fits! She can't get comfortable unless the extension is open, which means it's not being carried or used as a backpack. Amazon returns are starting to be a hassle for those of us in more rural areas - it will cost $5.99 to bring it to a UPS store - so since I bought this on sale, I may just keep it for "emergency" use.