Our firmness rating (1 soft to 10 hard), is based on our testing of each pillow. We use a compression and deflection test to determine where on the scale a pillow would fit. All of our testing is completely objective and qualitative; therefore, we can give a true rating that you can compare across pillows very easily. Every single pillow we review is subject to the same compression and deflection. Many companies and other review sites base firmness on subjective views which makes it extremely hard to compare. Because we use a machine to test firmness, it makes it very easy to apply a firmness rating to each pillow. Lastly, firmness is only one part of which pillow might be right for you. You must also consider sleeping position, sleeper weight, sleeper height, and sleeper preference to get the right pillow for you.