Explain how earned value management (EVM) can be used to control costs and measure project performance and speculate as to why it is not used more often. What are some general rules of thumb for deciding if cost variance, schedule variance, cost performance index, and schedule performance index numbers are good or bad?

EVM (Earned Value Management) is a systematic tool for project management, and also a technique that is used to check or track the progress/status of the objective and physical completion of the project work.

EVM is a technique which integrates the cost, scope and schedule of the project into a single parameter.

This technique is very useful for the project stakeholders, because it provides the status of the performance of the project.

In addition to the status of the performance of the project, EVM can also be used to show the past and current project performance and even forecast the future of the project performance based on the present and past performance using the statistical techniques.