This document discusses evaluating business plans and models. It outlines an approach to analyze a firm's past performance and key drivers of success. These drivers are then used to study how well the business plan forecasts correlate with projected performance in future planning periods. As an example, the document shows charts comparing an unnamed Firm X's actual past performance data to its optimistic planned values for profitability, which exceed actuals by a factor of 5-6 despite unchanged key drivers.