Amazon calculates a product’s star ratings using a machine learned model instead of a raw data average. The machine learned model takes into account factors including: the age of a review, helpfulness votes by customers and whether the reviews are from verified purchases.
I wear an Australian 6.5, which is usually a perfect 37 EU and US 6. The sizing on these told me to go for a 6.5W so I followed those instructions. They are not so large that they are flying off as I walk, but there is a good cm or more of space at the heel and they are a little loose. I would have been better off with a regular 6 US. Otherwise these are great, super comfy and well made.