In this section we meet two of the key tools of Lean Accounting. They are the value stream profit and loss account and the box school. The value stream profit and loss account is similar to a standard p&l, but is structured by business process, which we call value stream in lean, and it only comprises costs and revenues attributable to the value stream in order to calculate a value stream contribution. The box score is a type of balanced scorecard combining financial information with performance measures. Crucially, it is reported weekly to support prompt improvement activity to address problems.