In SaaS businesses, the Rule of 78 is used to plan how much revenue is needed each month to achieve a certain target. Accounting standards require that revenue be recognized ratably over time. This makes it hard to hit an annual goal when you have underperformance in the early part of a year. You simply can’t make up for lost time. Product managers should first quantify what has happened, understand why it happened, and use short and long-term tactics to achieve annual SaaS product revenue goals.