What is Earned Schedule? - An Emerging Earned Value Technique

The Earned Value Management (EVM) and the Critical Path Method (CPM) are widely accepted methods and are often used simultaneously to evaluate project performance. The common practice is to use EVM to evaluate the status of project cost and forecast the project's cost at completion while using CPM to evaluate the status of project schedule and forecast the project's completion time. However, EVM and CPM are based on different assumptions about the future and using them simultaneously can lead to the wrong decisions about the project.

The Earned Schedule (ES) allows EVM metrics to be transformed to time or duration metrics to enhance the evaluation of project schedule performance and to forecast the duration needed to complete the project. ES extends the use of EVM data to the assessment of the project's schedule status and the forecast of its completion time. These additional insights regarding the schedule are gained without the need for additional data collection and related cost. ES and EVM use the same underlying assumptions, leading to consistent forecasts about project outcomes. When combined with schedule analysis using CPM, ES enhances the project manager's understanding of project schedule status and forecasts and provides further support for making better, evidence-based decisions about the project's schedule and other parameters.

EVM, ES, and CPM are powerful methods that give executives, project managers, and other stakeholders the ability to visualize project cost and schedule status throughout the project life cycle and consequently manage projects, programs, and portfolios more effectively.

Keywords: Earned Schedule (ES); Earned Value Management (EVM); Critical Path Method (CPM); forecasting project outcomes; underlying assumptions.

Introduction

The Earned Value Management (EVM) method helps managers in making evidence-based decisions about project scope, resources, and cost; as a result, it supports effective project cost control and oversight. EVM gives the executive, program manager, project manager, and other stakeholders the ability to visualize project cost status throughout the project life cycle and consequently manage projects, programs, and portfolios more effectively. In its original form, EVM was used to evaluate project performance and forecast the cost of the project at completion. Usually, project control is established at the work package or cost account level. EVM data were generally not used to estimate the time needed to complete an activity, work package, or project, or to forecast their completion date. Project schedule network analysis techniques, such as the Critical Path Method (CPM) method, has been used widely to evaluate project schedule performance and forecasts of completion time. However, EVM and CPM are based on different assumptions about the future and using them simultaneously can lead the project manager to make the wrong decisions about the project. Extensions to EVM have been developed to use EVM data for schedule performance assessment and forecasts. The Earned Schedule (ES) concept allows EVM metrics to be transformed to time or duration metrics to enhance the evaluation of project schedule performance and to forecast the duration needed to complete the project. When combined with appropriate schedule analysis, this approach can enhance the project manager's understanding of the time estimate at completion of the project, and provide further insights for making better decisions about the project schedule and other related parameters. This paper highlights the main elements of EVM; presents the ES concept; compares ES with CPM; and integrates EVM, ES, and CPM.

The use of EVM in private industry and support by popular project management software packages have been rapidly growing in recent years. Details of the method were provided in Practice Standard for Earned Value Management—Second Edition (Project Management Institute, 2011) and in other sources (Anbari, 2003; Association for Project Management, 2006; Humphreys, 2002; Kerzner, 2009; Pr