Types of Baseline Changes
Not all changes to the plan are created equal. EVMS distinguishes between changes that the CAM can make internally and changes that require formal baseline change control. Understanding this distinction is critical — unauthorized changes are EVMS compliance violations, while failing to make necessary changes leads to a baseline that no longer represents the plan.
| Change Type | What Changes | Authorization | Traceability |
|---|---|---|---|
| Internal Replanning | Work sequence, resource assignments, budget phasing within the CA. Total CA budget and scope unchanged. | CAM authority, PM awareness | Documented in CA log. Before/after snapshots retained. |
| Rolling Wave Conversion | Planning packages converted to detailed work packages. No budget or scope change. | CAM authority | Planning package closure and new WP creation logged. |
| Internal Budget Transfer | Budget moved between control accounts within the same WBS branch. | Baseline Change Board | Formal BCR with from/to CAs, amounts, and justification. |
| Management Reserve Application | MR allocated to a CA for emergent scope. Increases distributed budget, decreases MR. | Program Manager | MR log entry with scope description and budget amount. |
| External Baseline Change (BCP) | Contract modification adds or removes scope and budget. Changes CBB and PMB. | Contracting Officer + PM | Contract mod, BCP, BCR tracing new budget to new scope. |
| Over-Target Baseline | PMB reset above CBB. New baseline exceeds contract budget. | Customer concurrence + PM | Reprogramming agreement. Historical data preserved separately. |
Internal Replanning Rules
Internal replanning is the CAM’s most frequently used change mechanism. As execution reveals reality, the CAM adjusts the remaining plan to reflect what they now know. This is expected, normal, and necessary. But it has strict boundaries.
✅ Allowed Internal Replanning
- Resequencing work packages to reflect updated execution priorities
- Shifting budget between future periods to match revised resource plans
- Converting planning packages into work packages
- Splitting a work package into two smaller ones (within the same CA budget)
- Reassigning resources from one WP to another within the CA
- Adjusting EV technique if work has not started and PM concurs
❌ Requires Formal Change Control
- Changing the total budget of the control account (up or down)
- Moving budget between control accounts
- Adding scope not currently in the CA
- Removing scope from the CA
- Changing past-period BCWS or BCWP
- Transferring budget from completed WPs to open WPs if it masks overruns
💡 The “Completed Work Package” Rule
Once a work package is complete (100% EV earned and all actuals posted), its budget should not be modified. Moving residual budget from a completed work package to an open one to cover an overrun is a form of “rubber baselining” that masks performance issues. If a completed WP has unspent budget, that variance is real information — it tells you the plan was conservative. If an open WP is overrunning, that is also real information. Do not let the former hide the latter.
The Baseline Change Proposal (BCP) Process
When a contract modification adds new scope, the program must incorporate it into the PMB through a formal process. The BCP documents the scope, budget, and schedule impact and flows them into the baseline.
Contract Modification Received
The contracting officer issues a contract modification authorizing new scope and budget. The new budget enters the system as undistributed budget (UB) or increases the CBB if accompanied by additional funding.
Impact Assessment
Affected CAMs assess the scope impact on their control accounts. They identify what work packages are needed, what resources are required, and how the new scope integrates with existing plans.
BCP Development
Program control develops the BCP documenting: scope description traced to contract language, budget allocation by CA, schedule milestones, and resource requirements. The BCP must balance — total budget allocated must equal the contract modification value.
Baseline Change Board Review
The program’s baseline change board reviews and approves the BCP. This board typically includes the PM, chief engineer, program control lead, and functional managers. The board ensures the change is properly scoped, budgeted, and scheduled.
Implementation
Approved changes are incorporated into the PMB. UB is distributed to control accounts. New work packages are created. The IMS is updated. All changes are logged with before/after values for traceability.
What Triggers a Rebaseline
A rebaseline — fundamentally restructuring the PMB — is a significant action. It should not be done casually, but it should not be avoided when the baseline has lost its value as a measurement standard.
| Trigger | Description | Typical Response |
|---|---|---|
| EAC >> CBB | Forecast total cost significantly exceeds the contract budget with no recovery path. | Over-Target Baseline (OTB). Reset PMB to achievable level. |
| Major Scope Restructure | Fundamental change in technical approach, WBS restructure, or large scope deletion/addition. | Comprehensive replanning. May require customer-approved rebaseline. |
| Schedule >> Contract Date | Completion date significantly beyond contract requirement with no recovery. | Over-Target Schedule (OTS). Reset schedule baseline to achievable dates. |
| Cumulative Variance Distortion | Cumulative variances so large that current-period data is meaningless relative to cumulative data. | Reprogramming to eliminate historical variances and reset cumulative counters. |
| Program Restructure | Organizational changes, contractor mergers, or fundamental program redirection. | Full rebaseline with customer concurrence. Treat as a new program start. |
Traceability Requirements
Every dollar in the PMB must be traceable from the contract through the CBB, through the PMB, to the control account, to the work package. This traceability chain is what makes EVMS auditable and what gives the data credibility.
| Traceability Element | From | To | Documentation |
|---|---|---|---|
| Contract to CBB | Contract price | CBB (price minus fee) | Contract, fee structure document |
| CBB to PMB + MR | CBB | PMB + Management Reserve | CBB reconciliation, MR log |
| PMB to CAs | Total PMB | Sum of all CA budgets + UB | RAM/budget crosswalk, CA authorization documents |
| CA to Work Packages | CA total budget | Sum of WP + PP budgets | CA plan, WP budgets, PP budgets |
| Change Traceability | Each baseline change | Before/after budget values by CA | BCR log, BCP documentation, MR log |
💡 The Audit Trail
During an IBR or EVMS surveillance review, the auditor will pick a random dollar amount and trace it from the contract to the work package. If any link in the chain is broken — if a budget increase cannot be traced to a contract mod, BCR, or MR allocation — it is a finding. Maintain the trail in real time; reconstructing it after the fact is painful and often impossible.
🎯 The Bottom Line
Change control is the discipline that preserves baseline integrity. Internal replanning keeps the plan current within the CAM’s authority. Formal changes adjust the PMB when scope, budget, or schedule genuinely change. Traceability ensures every dollar can be followed from contract to work package. Know the boundaries, follow the process, and maintain the trail. The baseline is only useful if everyone trusts it, and trust comes from disciplined change control. Next: The CAM Monthly Rhythm — how all of these processes come together in the monthly execution cycle.
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