Variance analysis is a quantitative review of the differences between plan versus actual values. Trend analysis is a quantitative review of a parameter over a period of time. Variance analysis is used to collect and assess the cost and schedule of a project. It is used to gauge whether the performance of a project parameter is deteriorating or improving. For example, we can use it for analyzing quality, productivity.  Trend analysis is used to gauge whether the performance of a project parameter is deteriorating or improving. For example, we can use it for analyzing quality, productivity. The main role of these two tools is course correction of a project.