The overall Which? test score is made up of the following star ratings, all determined by our rigorous lab tests.
How we test performance
Overall performance score combines several different tests. The overall performance includes how well the cot mattress supports your baby and child before we put it through our durability testing, how well the cot mattress moves moisture from leaks and spills away from the surface, and how much insulation the cot mattress provides (less insulation is better for your baby). We test each cot mattress on both sides using a 12kg dummy and a 21kg dummy. These dummies represent a one year old and a five year old and give you some idea of how supportive each cot mattress will be for your baby during his or her first five years.
How we test body support before durability test
We test each cot mattress on both sides using a 12kg dummy and a 21kg dummy. These dummies represent a one year old and a five year old and give you some idea of how supportive each cot mattress will be for your baby during its first five years. This score also helps make up the overall performance score for the cot mattress.
How we test permeability
Your baby is going to do a lot of living on his or her cot mattress. This will include all the sweat, tears, leaks and vomit that are a regular part of life with a baby. We test each cot mattress to see how well it does at allowing the mattress to transport moisture away from the body, keeping your baby comfortable and dry through the night. This score also helps make up the overall performance score for the cot mattress.
How we test durability
Each cot mattress goes through a durability test that is designed to simulate roughly three years of use by a baby. We then take stock of the mattress and measure the body support, again using dummies to represent a one year old and a five year old. We also measure the cot mattress to see if it has changed in height (or thickness) and firmness.
How we test change in support after durability test
We test each mattress for body support before we put it through our durability testing, and again after. We then work out if there have been any changes in the ability of the cot mattress to support both baby (approximately one year old) and child (approximately five years old). A five star means that there is little change between body support before and after durability testing. While a one star means that there has been a huge change. This measurement makes up part of the score for overall durability.
How we test washability
Cot mattresses will need to be cleaned often. So we have tested each cot mattress to see how easy each is to clean. We scrutinise the cleaning instructions and whether or not the cot mattress comes with a removable, washable cover. If the cot mattress has a cover we then test each mattress cover for how easy it is to remove, launder and refit. We wash each cover several times to see how it holds up to use.