Cost Variance (CV), and Schedule Variance (SV)

Cost Variance (CV) and Schedule Variance (SV)

Introduction: Why This Matters

Cost Variance (CV) and Schedule Variance (SV) are the first diagnostic indicators in Earned Value Management. They allow project managers to assess whether a project is ahead or behind schedule, and whether it is under or over budget. Without these metrics, stakeholders may only see raw expenditures or task completion percentages, which often fail to tell the full story.

On the PMP exam, CV and SV are frequently tested because they are straightforward to calculate yet easy to misinterpret. In practice, they are critical for early detection of project slippage or overruns, enabling corrective action before small problems escalate into major failures.

Purpose and Objectives

Primary Purpose: To measure cost and schedule health in a quantifiable way, supporting accurate project control.

Key Objectives:

  • Define and calculate Cost Variance (CV) and Schedule Variance (SV).
  • Interpret positive, negative, or zero values.
  • Distinguish between efficiency and inefficiency in both cost and schedule.
  • Use CV and SV in project reporting and corrective action planning.
  • Recognize common exam traps related to variances.

Overview

CV and SV use Earned Value inputs to show whether performance is trending favorable or unfavorable against the baseline.

  • Cost Variance (CV): Compares the value of work performed to the actual cost of doing that work.
  • Schedule Variance (SV): Compares the value of work performed to the value of work that was planned.

Characteristics

  • Baseline-driven: EV and PV are budget-based values tied to the approved plan.
  • Fast diagnostics: A single positive or negative sign tells you whether performance is favorable or unfavorable.
  • Currency-based: Both CV and SV are expressed in monetary terms, not percentages or time units.
  • Action-oriented: Variances are intended to trigger analysis and corrective action, not just reporting.

Practical Example

Context: A new airline check-in system project has a Budget at Completion (BAC) of $4,000,000. At month six:

Activities:

  • Inputs at Month 6: EV = $1,800,000; PV = $2,000,000; AC = $2,200,000.
  • Calculate CV and SV: Apply the variance formulas to diagnose cost and schedule health.

Outcome: CV = -$400,000 (over budget) and SV = -$200,000 (behind schedule). The project has spent more than planned and completed less work than scheduled. Without intervention, delays and overruns will compound.

Common Pitfalls

Interpretation Mistakes

  • Pitfall: Confusing EV with AC and treating EV as “money spent.”
  • Prevention: Remember EV is budget-based value of completed work, while AC is actual money spent.

Ignoring Early Warning Signals

  • Pitfall: Assuming small negative variances can be ignored.
  • Prevention: Treat any negative trend as a trigger for root cause analysis and corrective planning.

Unit Confusion

  • Pitfall: Forgetting that SV is measured in currency, not time.
  • Prevention: SV is “value behind or ahead,” not “days behind or ahead.”

Incomplete Reporting

  • Pitfall: Reporting only CV or only SV.
  • Prevention: Evaluate both cost and schedule together to avoid misleading conclusions.

Sensei Tip : When you see “variance,” think subtraction. CV is EV minus AC. SV is EV minus PV. Then check the sign. Positive is favorable, negative is unfavorable.

Exam Alert : The exam loves to bait you into treating SV like a time metric. SV is always measured in value (currency). If an answer choice talks about “days behind” using SV, it is probably a trap.

Exam Lens

Patterns on the PMP Exam:

  • Expect direct formula questions using EV, PV, and AC.
  • Some situational questions will ask you to interpret whether a project is ahead/behind or under/over budget.
  • Watch for distractors that suggest SV is measured in time rather than value.

Sample Question

Question: A project has EV = $350,000, PV = $400,000, and AC = $300,000. What do CV and SV indicate?

  1. CV = +$50,000 (under budget), SV = -$50,000 (behind schedule)
  2. CV = -$50,000 (over budget), SV = +$100,000 (ahead of schedule)
  3. CV = +$100,000 (under budget), SV = -$50,000 (behind schedule)
  4. CV = -$100,000 (over budget), SV = +$50,000 (ahead of schedule)

Correct Answer: A. CV = +$50,000 (under budget) and SV = -$50,000 (behind schedule), because CV = EV – AC and SV = EV – PV.

Quick Recap Table

Metric Formula Positive Negative Exam Watch Point
CV EV – AC Under budget Over budget Do not confuse with CPI
SV EV – PV Ahead of schedule Behind schedule Measured in value, not time

Key Takeaways

  • CV measures cost performance against actual spend, while SV measures schedule performance against planned value.
  • Positive is favorable, negative is unfavorable, and zero means you are exactly on target.
  • Variances provide early warnings that allow corrective action before issues compound.
  • Always assess CV and SV together for a complete performance picture.
  • On the exam, expect interpretation traps, especially around SV being value-based rather than time-based.

Next Step

With CV and SV established, we now turn to Cost Performance Index (CPI) and Schedule Performance Index (SPI), which build on these variances to measure efficiency ratios that are easier to compare across projects.

Bibliography

Project Management Institute. (2021). A Guide to the Project Management Body of Knowledge (Project Management Body of Knowledge) (7th ed.). PMI.

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