Earned Value Management Made Practical

What EVM Actually Tells You

Earned Value Management integrates three dimensions of project performance into a single framework:

1. What did we plan to accomplish by now? (Planned Value — PV) 2. What did we actually accomplish? (Earned Value — EV) 3. What did it cost to accomplish that? (Actual Cost — AC)

From these three numbers, you can derive everything you need to know about project health — and predict the future with surprising accuracy.

The Core Metrics

Schedule Performance Index (SPI)

Formula: SPI = EV ÷ PV

Interpretation:

• SPI = 1.0: Exactly on schedule
• SPI > 1.0: Ahead of schedule
• SPI < 1.0: Behind schedule

Example: You planned to complete £100K of work by now (PV = £100K). You actually completed £85K of work (EV = £85K). SPI = 0.85 — you're 15% behind schedule.

Cost Performance Index (CPI)

Formula: CPI = EV ÷ AC

Interpretation:

• CPI = 1.0: Exactly on budget
• CPI > 1.0: Under budget (getting more value per pound spent)
• CPI < 1.0: Over budget (spending more than planned for the work completed)

Example: You completed £85K of work (EV = £85K). It cost you £95K to do it (AC = £95K). CPI = 0.89 — you're 11% over budget.

Schedule Variance (SV) and Cost Variance (CV)

• SV = EV - PV (negative = behind schedule)
• CV = EV - AC (negative = over budget)

These give you the absolute variance in currency terms, which is often more intuitive for stakeholders than indices.

Making EVM Work in Practice

Step 1: Create a Performance Measurement Baseline

Before the project starts, create a time-phased budget that shows how much work (in £) should be completed by each reporting period. This is your Planned Value curve.

Practical approach:

• Break the project into work packages (epics or deliverables)
• Assign a budget to each work package
• Schedule when each work package will be completed
• Sum the budgets by period to create the cumulative PV curve

Step 2: Measure Earned Value

At each reporting period, determine how much work has been completed. This is the hardest part — you need an objective way to measure progress.

Methods for measuring EV:

• 0/100 rule: Work package earns no value until 100% complete. Simple but conservative — large work packages show no progress until done.
• 50/50 rule: 50% earned when started, 50% when complete. Good for short-duration work packages.
• Milestone-weighted: Assign % complete to predefined milestones within a work package. Most accurate for longer work packages.
• % complete (subjective): The PM estimates completion percentage. Least reliable — prone to the "90% done" syndrome.

Recommendation: Use 0/100 for work packages shorter than 2 weeks. Use milestone-weighted for longer packages. Avoid subjective % complete.

Step 3: Track Actual Cost

Record what you've actually spent. This should come from your finance system, not from estimates:

• Labour costs (hours × rate for each team member)
• Vendor and contractor costs
• Infrastructure and tooling costs
• Any other direct project costs

Step 4: Calculate and Report

At each reporting period (weekly or fortnightly): 1. Sum PV for all work packages scheduled to be complete by now 2. Sum EV for all work packages actually completed (using your chosen method) 3. Sum AC from finance data 4. Calculate SPI, CPI, SV, CV 5. Calculate forecasts (see below)

Forecasting With EVM

The real power of EVM is prediction. Once you have a few periods of data, you can forecast:

Estimate at Completion (EAC)

Formula: EAC = BAC ÷ CPI

Where BAC = Budget at Completion (total project budget)

Interpretation: If current cost performance continues, the project will cost EAC to complete.

Example: BAC = £500K, CPI = 0.89. EAC = £500K ÷ 0.89 = £562K. The project is forecast to be £62K over budget.

Estimate to Complete (ETC)

Formula: ETC = EAC - AC

Interpretation: How much more money is needed to finish the project.

Variance at Completion (VAC)

Formula: VAC = BAC - EAC

Interpretation: The expected budget overrun (negative) or underrun (positive) at project end.

The Critical Insight: CPI Rarely Improves

Research consistently shows that CPI measured at the 20% completion point is a reliable predictor of final project cost. Once a project establishes a CPI below 1.0, it rarely recovers without significant intervention (scope reduction, additional resources, or process change).

This means: if CPI is 0.85 at the 20% mark, the project will likely finish 15% over budget unless you take corrective action now. Don't wait and hope it improves — it won't.

Reporting EVM to Stakeholders

The Executive View

Present three things: 1. SPI and CPI with trend (improving, stable, declining) 2. EAC — what the project is forecast to cost 3. Recommended action — what needs to change (if anything)

Example narrative: "SPI is 0.92 (slightly behind schedule) and CPI is 0.95 (slightly over budget). At current performance, the project will cost £525K against a £500K budget — a £25K overrun. Recommendation: reduce scope by deferring the reporting module to Phase 2, which brings EAC back to £498K."

The S-Curve Chart

Plot PV, EV, and AC on a time-phased chart. This gives stakeholders an intuitive visual:

• EV below PV = behind schedule
• AC above EV = over budget
• The gap between curves shows the severity

EVM in Agile/Hybrid Projects

EVM works in Agile environments with adaptation:

• Work packages = Epics or Features (not individual stories)
• Planned Value = Story points planned per sprint × cost per point
• Earned Value = Story points completed per sprint × cost per point
• Actual Cost = Team cost per sprint (usually fixed for stable teams)

For fixed-cost teams (salaried), CPI is less useful (AC is constant regardless of output). Focus on SPI — are you delivering the planned scope on schedule?

Common EVM Mistakes

Measuring % complete subjectively: The "90% done" problem. Fix: use objective completion criteria (0/100 or milestone-weighted).

Not updating the baseline: The baseline should only change through formal change control. If you update it every time you're behind, EVM becomes meaningless.

Reporting without action: EVM data without recommended corrective action is just numbers. Always pair metrics with "so what should we do?"

Over-precision: Calculating EVM to the penny when estimates have ±20% accuracy. Fix: report to appropriate precision. SPI of 0.95 vs 0.94 is noise — both mean "slightly behind."

Ignoring early warnings: CPI below 0.9 at the 20% mark is a serious warning. Don't wait until 80% to act.

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Download the [Project Plan & Schedule template](/templates) for a project plan with built-in earned value tracking.