One review, one vote. Brands share the same review to several retailers and several sizes. We match each review by its text and count it once, so a product's combined total can be lower than the two retailer totals added together.
Same product, matched by name and size. We pair Boots and Tesco listings when brand, product line, size and type agree. Different sizes are kept as separate products.
Product-specific reviews only. Brands often show one pool of reviews across a whole range: other sizes, the matching conditioner, sometimes different products. We leave out any review that also appears on another product, so every score and summary reflects only reviews of that exact product. Copies of the same review at Boots and Tesco for the same product are kept and counted once. Products whose reviews are all shared with other products are not listed.
Positives and negatives. We look for themes that recur across many reviews and describe them in our own words. Delivery complaints and reviews of other products in the range are left out of the summary. Where there are 20 or more written reviews, a positive needs at least 5 reviews and 2% of written reviews, and a negative needs at least 5 reviews and 8% of 1 to 3-star reviews. With fewer written reviews, a theme needs two mentions (one when there are only one or two reviews), and the page says the summary is based on a small number of reviews.
Best for. For each need, such as dandruff or curly hair, we find the reviews that mention it and look at how those reviewers rated each product. A product competes if its name says it is made for that need, or if at least 25 reviewers (and 10% of its written reviews) mention it. It needs at least 10 such reviews, and scores are pulled towards the average so a few glowing reviews can’t win alone. Matching is by keywords, so it can miss reviews or pick up a mention that isn’t really about the reviewer’s own hair.
Thin data. Products with fewer than 10 reviews show a count and a short summary but no score.