A visual interface for model-fitting

We describe a tool which supports the activity of a human being in fitting a mathematical model to measured or simulated data. The tool offers two principal advantages; its use requires a minimum of statistical knowledge, and its visual and interactive nature ensures that its use is intuitive. The tool is novel in that, in the iterative and often exploratory construction of a model, it represents graphically the benefit of all possible single changes to the existing model; a single selection action suffices to add a new term to a model or to remove it.