Percentile

Tom is in the first percentile for maths in Australia.

This test places you in the 90th percentile of the population.

The study based on UCLA research found that obese children—those with a Body Mass Index (BMI) in the 95th percentile or above—are nearly two times more likely to have three or more physical or mental conditions than kids with a healthy weight.

She is highly intelligent—she has an IQ in the top percentile.

Also, doctors are much more interested in the relationship between the percentiles for weight and length than they are the numbers themselves. Healthy babies tend to land in somewhat similar percentiles for both metrics and are probably getting enough nutrition. This goes for those babies who don’t chart at all. Because it is impossible for researchers to determine what is the largest and smallest possible weight and length for babies, designers begin the charts at the fifth percentile and end them at the 95th percentile. This means 10% of babies are, like my son, unchartable.