The scale is fine. It's either logarithmic or really close to it. The centre is 1 (base + 0%). Where base = 1. The first step to the right is 5/4 (base + 25%)

The scale is fine. It's either logarithmic or really close to it. The centre is 1 (base + 0%). Where base = 1. The first step to the right is 5/4 (base + 25%). The first step to the left is 4/5 (base - 20%). The distance represented is a multiplication by 5/4. (4/5 * 5/4 = 1. 1*5/4 = 5/4). And so on. The second steps are 3/2 and 2/3 (base +50% and base -34%). The third step on the right is 2/1, and if the one on the left were present, it would probably be 1/2. From visual inspection, the relative lengths (apart from those who are equal) also look correct. For instance If you start at 5/4 and move a similar length to the right, you should get (5/4)^2 = 25/16. This is a bit more than 3/2. So the distance from 1 to 5/4 is longer than from 5/4 to 3/2. Now, this IS indeed good evidence that better STEM education is needed.