pra-earned-value

name	pra-earned-value
description	Measure project cost/schedule performance and forecast final outcomes with Earned Value Management using the PRA package. Use when a user provides a budget (BAC), a planned schedule curve, and actual costs/progress and wants SPI, CPI, variances, or an Estimate at Completion (EAC).

When to use

The user has a Budget at Completion, a cumulative planned-value curve, current progress, and actual costs, and wants performance indices or forecasts.

MCP tool

evm_analysis_tool(bac, schedule_json, time_period, actual_per_complete, actual_costs_json, cumulative) runs the complete ANSI/EIA-748 suite in one call — do not chain the individual metrics manually.

• bac: Budget at Completion (total planned budget).
• schedule_json: JSON array of cumulative planned completion fractions, e.g. [0.1, 0.2, 0.4, 0.7, 1.0].
• time_period: current period (1-based index into the schedule).
• actual_per_complete: actual percent complete as a decimal (e.g. 0.35).
• actual_costs_json: JSON array of actual costs per period, e.g. [10000, 22000, 37000].
• cumulative: "true" if the costs are already cumulative, else "false".

What it returns

• Baseline: PV = BAC × planned%, EV = BAC × actual%, AC.
• Variances: SV = EV − PV (schedule), CV = EV − AC (cost).
• Indices: SPI = EV / PV, CPI = EV / AC (>1 is favorable).
• Forecasts (EAC):
  • Typical (CPI-based): BAC / CPI — current trend continues.
  • Atypical: AC + (BAC − EV) — current variance is a one-off.
  • Combined: AC + (BAC − EV) / (CPI × SPI) — schedule pressure affects cost.
• ETC = EAC − AC, VAC = BAC − EAC, TCPI = efficiency required on remaining work to hit the target.

Warning thresholds

• CPI or SPI below ~0.9 signals a project in trouble.
• CPI rarely improves by more than ~10% after a project is 20% complete.
• TCPI substantially above 1.0 is an unrealistic recovery target.

References

• ANSI/EIA-748 Earned Value Management Systems standard.
• DOE EVMS Interpretation Handbook (EVMSIH v2.0).