We have been asking the public if they can tell the difference between two cups of tea: one made with milk added first, the other with tea added first.

This experiment is run by Kristian Glenny and Anna Galloway as part of a summer studentship at the University of Sheffield. It was originally performed in the 1920s by one of the founding fathers of modern statistics, Ronald Fisher. We chose to recreate Fisher’s study because we wanted to take a topic that everyone can relate to and use it to illustrate some key features of scientific investigation.

What follows are some of the key considerations that went into designing this experiment.