The EDA allows scientists to create a visual representation of an animal experiment by laying out its key elements — hypothesis, experimental method and planned analysis — in logically connected, coloured boxes. The software then uses a built-in set of rules to spot potential prob¬lems, and suggests refinements. These may be simple — the researcher hasn’t specified how to randomize animals to the control or treatment arm — or more complex: there are potential confounding variables in the control and trial arms. The tool can also assist scientists with calculating the sample size needed to ensure a sta¬tistically robust result, or with randomization (see D Cressey, Nature 531:126, 2016; Percie du Sert1 et al., Nat Meth 14:1024, 2017). Registration required.