SkarpChapter 5 of 21
Cost Management Essentials: Estimates, Baselines, and Reserves
Money talk on projects goes far beyond a single budget line—discover how estimates, baselines, and reserves really work and how the exam expects you to classify and roll them up.
Big Picture: How Cost Management Fits Your Project
Where Cost Management Fits
Cost management turns stakeholder and governance decisions into numbers. It underpins budgeting, tracking, and explaining how money is used on the project.
Five Core Ideas
You will connect: cost estimating techniques, time‑phased cost baselines, contingency vs management reserves, how budgets roll up, and basic earned value (EV, PV, AC).
Links to Earlier Modules
Governance (phase gates, change control) affects the cost baseline. Sponsors own funding; functional managers give cost inputs; the project manager integrates all of it.
Exam Mindset
CAPM questions often ask you to classify (which type of reserve or estimate?) and to roll up numbers (what is in the baseline vs total budget?). Keep that in mind as you learn.
Cost Estimating Foundations: Levels and Accuracy
Levels of Estimates
ROM is early and coarse, budget is mid‑range, and definitive is detailed and most accurate. The more detail and data you have, the tighter the expected accuracy.
Inputs to Estimating
You need clear scope, a work breakdown structure, historical data, expert judgment, and explicit assumptions and constraints to produce realistic cost estimates.
Cost Categories
Direct costs tie directly to the project; indirect costs are shared overhead. Fixed costs stay the same; variable costs change with volume or usage.
Common Exam Trap
Watch for questions that use a rough order of magnitude where a definitive estimate is needed, or that pretend the PM can control corporate overhead rates.
Analogous vs Parametric Estimating: Choosing the Right Tool
Analogous Estimating
Top‑down: use cost from a previous, similar project or activity. It is fast and cheap but less accurate, and relies heavily on expert judgment.
Parametric Estimating
Data‑driven: apply a cost per unit or other statistical relationship. It is more consistent and accurate if good historical data exists.
Exam Clues
Words like 'similar project' and 'little detail' hint at analogous. Phrases like 'cost per unit' or 'productivity rate' point to parametric.
Choosing Between Them
Use analogous when you need a quick, high‑level estimate. Use parametric when you have reliable data and want better accuracy across many units.
Worked Examples: Analogous vs Parametric in Practice
Scenario 1: Office Move
Past move cost $100,000 for 100 people; you estimate $120,000 for 120 people using cost per person. This is parametric estimating.
Scenario 2: Campaign
You base the new campaign budget on the total cost of a similar past campaign, adjusted slightly. This is analogous estimating.
Scenario 3: Agile Feature Bundle
Using cost per iteration tied to historical velocity (story points) to estimate a bundle cost is parametric estimating.
Scenario 4: New Product Line
An executive uses experience from a similar launch elsewhere to give a ballpark figure. That is analogous estimating.
Bottom‑Up and Three‑Point Estimating: Building from the Ground Up
Bottom‑Up Estimating
Estimate costs at the work package level of the WBS and then roll them up. It is detailed and accurate when scope is clear but takes more time.
Three‑Point Estimating
Use optimistic, most likely, and pessimistic values to reflect uncertainty. A simple average is (O + M + P) / 3, called a triangular distribution.
Combining the Two
You can apply three‑point estimates to each work package and then aggregate them bottom‑up to form more realistic project cost totals.
Exam Distinction
Bottom‑up is detailed and slow; analogous is high‑level and fast. Watch wording about estimating 'each work package' versus 'similar past project'.
Reserves 101: Contingency vs Management Reserve
Contingency Reserve
Covers known‑unknowns: identified risks that may or may not occur. It is calculated and managed by the PM and included in the cost baseline.
Management Reserve
Covers unknown‑unknowns: unforeseen work within scope. It is controlled by senior management and is not part of the cost baseline.
Baseline vs Total Budget
Cost baseline = planned work + contingency. Total project budget = cost baseline + management reserve.
Exam Traps on Reserves
Do not put management reserve into the baseline. Do not treat contingency as random padding. Spending management reserve usually requires change control.
Rolling Up Estimates and Reserves into the Budget
Step 1: Planned Work
Three work packages total $40,000 using bottom‑up estimating. This is the sum of planned activity costs before reserves.
Step 2: Add Contingency
Identified risks lead to a $5,000 contingency reserve. Planned work plus contingency equals a $45,000 cost baseline.
Step 3: Add Management Reserve
Management adds a 10% management reserve, $4,500, outside the baseline. Total project budget becomes $49,500.
Step 4: Authority
The PM can use contingency for identified risks. Using management reserve usually requires approval and a change to the baseline.
Time‑Phased Cost Baseline: Turning a Number into a Curve
What is Time‑Phased?
A time‑phased cost baseline spreads the approved baseline (planned work plus contingency) across time periods, often forming an S‑curve.
Simple Example
Assign design, development, and testing costs plus contingency to Months 1–3, then compute the cumulative planned spending each month.
Using It for Control
During execution you compare actual cost (AC) against planned value (PV) from this time‑phased baseline at each reporting date.
Exam Signal
If a question mentions tracking costs over time with an S‑curve or cumulative plan, it is referring to the time‑phased cost baseline.
Earned Value Basics: EV, PV, and AC
Planned Value (PV)
PV is the budgeted cost of the work that should be done by a certain date, taken from the time‑phased cost baseline.
Earned Value (EV)
EV is the budgeted cost of the work actually completed by that date, not what you actually spent.
Actual Cost (AC)
AC is the actual money spent for the work performed so far, based on invoices, timesheets, and other records.
Link to Schedule Variance
Schedule variance is defined as the difference between earned value and planned value (SV = EV − PV), indicating schedule performance.
Quick Check: Estimating Techniques and Reserves
Test your understanding of key distinctions before moving on.
A project manager is early in a project with limited detail. She uses the total cost of a similar past project and adjusts it slightly for inflation. She also adds a small amount of budget for identified technical risks. Which pair of techniques/reserves is she using?
- Parametric estimating and management reserve
- Analogous estimating and contingency reserve
- Bottom‑up estimating and contingency reserve
- Analogous estimating and management reserve
Show Answer
Answer: B) Analogous estimating and contingency reserve
Using the total cost of a similar past project with slight adjustment is analogous estimating. Adding budget for identified technical risks is contingency reserve, which covers known‑unknowns and is part of the cost baseline.
Quick Check: Baseline vs Total Budget and EV Concepts
Apply what you learned about baselines and earned value.
A project has a cost baseline of $500,000 and a management reserve of $50,000. After two months, planned value (PV) is $200,000, earned value (EV) is $180,000, and actual cost (AC) is $190,000. Which statement is MOST accurate?
- The total project budget is $500,000 and the project is ahead of schedule.
- The total project budget is $550,000 and the project is behind schedule.
- The total project budget is $550,000 and the project is under budget for the work performed.
- The total project budget is $500,000 and the project is over budget for the work performed.
Show Answer
Answer: B) The total project budget is $550,000 and the project is behind schedule.
Total project budget = cost baseline ($500k) + management reserve ($50k) = $550k. EV ($180k) is less than PV ($200k), so the project is behind schedule in terms of value delivered. AC is not needed to answer this specific question.
Thought Exercise: Build a Mini Time‑Phased Baseline
Work through this mentally or jot it down. This mirrors how CAPM scenario questions are framed.
Scenario
You are managing a 3‑month training project. Bottom‑up estimates for planned work are:
- Month 1: Needs analysis and design = $10,000
- Month 2: Content development = $18,000
- Month 3: Delivery and evaluation = $12,000
Risk analysis identifies:
- R1 (Month 2): Possible rework of training materials, EMV = $2,000
- R2 (Month 3): Possible extra evaluation sessions, EMV = $1,000
Senior management adds a management reserve of $3,000.
Your tasks
- Compute the planned work total.
- Add contingency for R1 and R2 to find the cost baseline.
- Add management reserve to find the total project budget.
- Sketch a simple time‑phased baseline by month (you can just list the numbers).
- Decide which number (baseline or total budget) you would use as the reference for earned value calculations.
Pause and answer before reading the solution.
Solution walkthrough
- Planned work = $10,000 + $18,000 + $12,000 = $40,000.
- Contingency = $2,000 + $1,000 = $3,000 → cost baseline = $43,000.
- Total project budget = cost baseline $43,000 + management reserve $3,000 = $46,000.
- One possible time‑phasing of the cost baseline:
- Month 1: $10,000 (no related risks) → cumulative PV = $10,000
- Month 2: $18,000 + $2,000 contingency = $20,000 → cumulative PV = $30,000
- Month 3: $12,000 + $1,000 contingency = $13,000 → cumulative PV = $43,000
- For earned value, you use the cost baseline (time‑phased) as the reference, not the total budget including management reserve.
Key Terms Review: Costs, Baselines, and EV
Flip these cards mentally to reinforce terminology that often appears in CAPM questions.
- Analogous estimating
- A top‑down estimating technique that uses the actual cost of a previous, similar project or activity as the basis for estimating the cost of the current project or activity; fast but less accurate and reliant on expert judgment.
- Parametric estimating
- An estimating technique that uses a statistical relationship between historical data and other variables (such as cost per unit, productivity rates, or learning curves) to calculate a cost estimate.
- Bottom‑up estimating
- An estimating method where costs are estimated at the work package or detailed activity level and then aggregated upward through the work breakdown structure to determine total project costs.
- Work package
- The work defined at the lowest level of the work breakdown structure for which cost and duration are estimated and managed.
- Contingency reserve
- Budget (or time) included in the cost baseline to address identified risks (known‑unknowns) that remain after risk responses are planned; controlled by the project manager.
- Management reserve
- Budget set aside for unforeseen work within the project scope that has not yet been identified; not part of the cost baseline and typically controlled by senior management or the sponsor.
- Cost baseline
- The approved, time‑phased budget for the project work plus contingency reserve, used as the basis for measuring and controlling cost performance.
- Total project budget
- The sum of the cost baseline and management reserve; represents the full amount of funding authorized for the project.
- Planned value (PV)
- The authorized budget assigned to work scheduled to be completed by a given time, derived from the time‑phased cost baseline.
- Earned value (EV)
- The measure of work performed expressed in terms of the budget authorized for that work; the budgeted cost of the work actually completed.
- Actual cost (AC)
- The realized cost incurred for the work performed during a specific time period.
- Schedule variance
- A measure of schedule performance expressed as the difference between earned value and planned value.
Key Terms
- work package
- The work defined at the lowest level of the work breakdown structure for which cost and duration are estimated and managed.
- cost baseline
- The approved, time‑phased budget for the project work plus contingency reserve, used as the basis for measuring and controlling cost performance.
- actual cost (AC)
- The realized cost incurred for the work performed during a specific time period.
- earned value (EV)
- The measure of work performed expressed in terms of the budget authorized for that work; the budgeted cost of the work actually completed.
- schedule variance
- A measure of schedule performance expressed as the difference between earned value and planned value.
- management reserve
- Budget set aside for unforeseen work within the project scope that has not yet been identified; not part of the cost baseline and typically controlled by senior management or the sponsor.
- planned value (PV)
- The authorized budget assigned to work scheduled to be completed by a given time, derived from the time‑phased cost baseline.
- contingency reserve
- Budget (or time) included in the cost baseline to address identified risks (known‑unknowns) that remain after risk responses are planned; controlled by the project manager.
- analogous estimating
- A top‑down estimating technique that uses the actual cost of a previous, similar project or activity as the basis for estimating the cost of the current project or activity; fast but less accurate and reliant on expert judgment.
- bottom-up estimating
- An estimating method where costs are estimated at the work package or detailed activity level and then aggregated upward through the work breakdown structure to determine total project costs.
- total project budget
- The sum of the cost baseline and management reserve; represents the full amount of funding authorized for the project.
- parametric estimating
- An estimating technique that uses a statistical relationship between historical data and other variables (such as cost per unit, productivity rates, or learning curves) to calculate a cost estimate.
- work breakdown structure
- A hierarchical decomposition of the total scope of work to be carried out by the project team to accomplish the project objectives and create the required deliverables.