Inter-rater reliability

Inter-rater reliability is a way of making sure two people (or more!) agree on something. It's like having two friends look at a painting and make sure they both think it's a good painting. Or it's like two people counting the number of apples they see in a picture - if they both say there are 8 apples, that's an example of inter-rater reliability. It's important because it helps us make sure we can trust the information we get from other people.