Final answer:
Earned Value (EV) is the method used to measure a project's progress by providing a comprehensive picture of both time and cost performance. It integrates project scope, cost, and schedule, unlike other measures that focus on specific aspects of project performance.
Step-by-step explanation:
Earned Value (EV) is used to measure the project's progress by giving a more complete picture of overall project performance in relation to both time and cost. It integrates project scope, cost, and schedule measures to help the project management team assess and measure the project performance and progress. Other options, such as Schedule Performance Index (SPI) and Cost Performance Index (CPI), are related to earned value management (EVM) but focus on specific aspects. The SPI measures project progress achieved against the project schedule, while the CPI measures the value of work against the actual cost. Variance Analysis is another important tool, which involves determining the cause of variances between planned and actual performance, but it does not integrate cost and schedule performance into a single measure like EV.