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 read a lot of reviews and did a fair amount of research before deciding to buy this. Very happy with my purchase, the pen is well made and authentic. I’ve only used it once at home, and had a session at a salon and so far am a fan!