How do you choose between Earned Schedule and Earned Value for project performance measurement?

1 What is EVM?

EVM is a project management technique that integrates scope, schedule, and cost information to monitor and control project performance. EVM uses three key values to calculate various performance indicators: Planned Value (PV), Earned Value (EV), and Actual Cost (AC). PV is the budgeted cost of the work scheduled to be done by a certain date. EV is the budgeted cost of the work actually completed by that date. AC is the actual cost incurred for the work done by that date.

2 What is ES?

ES is a variation of EVM that focuses on schedule performance instead of cost performance. ES uses the same PV and AC values as EVM, but replaces EV with Earned Schedule (ES), which is the planned duration of the work actually completed by a certain date. ES also calculates different performance indicators, such as Schedule Performance Index (SPI(t)), which is the ratio of ES to PV, and Schedule Variance (SV(t)), which is the difference between ES and PV.

3 What is EV?

EV is the original version of EVM that focuses on cost performance instead of schedule performance. EV uses the same PV, EV, and AC values as EVM, and calculates performance indicators such as Cost Performance Index (CPI), which is the ratio of EV to AC, and Cost Variance (CV), which is the difference between EV and AC. EV also calculates schedule performance indicators, such as Schedule Performance Index (SPI), which is the ratio of EV to PV, and Schedule Variance (SV), which is the difference between EV and PV.

4 Why use ES?

ES is a more accurate and reliable measure of schedule performance than EV, because it reflects the actual progress of the project in terms of time, not cost. ES also avoids the problem of misleading SPI and SV values that can occur when using EV, especially when there are significant changes in the project scope, budget, or schedule. ES can help project managers identify and correct schedule deviations early, and improve their forecasting and planning abilities.

5 Why use EV?

EV is a more widely used and accepted measure of cost performance than ES, because it reflects the actual value of the work done, not the time spent. EV also provides a consistent and standardized way of comparing and reporting project performance across different projects, organizations, and industries. EV can help project managers control and optimize their project costs, and demonstrate their accountability and value to stakeholders.

6 How to choose?

There is no definitive answer to whether ES or EV is better for measuring project performance, as both methods have their strengths and limitations. The choice depends on various factors, such as the nature and complexity of the project, the availability and quality of data, the expectations and preferences of the stakeholders, and the project management tools and processes used. The best practice is to use both ES and EV together, as complementary metrics that provide a holistic and balanced view of project performance.