PSP — AACE Planning & Scheduling Professional Quick Review

Purpose of this Quick Review

This Quick Review is for candidates preparing for the AACE International AACE Planning & Scheduling Professional (PSP) exam, code PSP. It is designed as a fast, practical refresher before you move into topic drills, mock exams, and detailed explanations.

Use it to check whether you can:

• Build a defensible project schedule from scope, WBS, calendars, logic, and resources.
• Interpret CPM results correctly, especially float, critical path, constraints, and progress updates.
• Recognize weak schedule practices and common exam traps.
• Connect schedule data to performance measurement, risk, change, and delay analysis.
• Practice with PM Mastery practice, original practice questions, and a question bank after reviewing the concepts.

This page is PM Mastery review support and is not affiliated with AACE International.

High-Yield Review Map

Planning Comes Before Scheduling

A strong schedule starts with a strong plan. The exam can test whether you understand that a schedule is not just a list of dates. It is a time-phased model of execution.

Core Planning Inputs

Planning vs. Scheduling

A common exam mistake is to jump directly into CPM calculations without checking whether the schedule has a valid planning basis.

Schedule Development Workflow

    flowchart TD
	    A[Define scope and WBS] --> B[Identify activities and milestones]
	    B --> C[Estimate durations]
	    C --> D[Assign calendars and resources]
	    D --> E[Develop network logic]
	    E --> F[Calculate CPM dates and float]
	    F --> G[Review constraints and reasonableness]
	    G --> H[Resource review and optimization]
	    H --> I[Risk and contingency review]
	    I --> J[Approve baseline]
	    J --> K[Status, update, forecast, and control]

Use this workflow as a mental checklist. If a question describes a schedule with dates but no logic, no scope traceability, or no update discipline, the schedule may not be reliable.

Work Breakdown Structure and Activity Definition

The WBS organizes project scope into deliverables and manageable components. Schedule activities should be detailed enough to manage work, but not so detailed that the schedule becomes impossible to maintain.

Good Activity Characteristics

A well-defined schedule activity usually has:

• A clear scope of work.
• A responsible party.
• A measurable start and finish.
• A realistic duration.
• Logical predecessor and successor relationships.
• Assigned calendar assumptions.
• Resource or quantity basis when appropriate.
• Progress measurement method.

Activity Detail Decision Rules

CPM Fundamentals

Critical Path Method scheduling calculates early and late dates based on activity durations, logic, calendars, and constraints. The critical path is the longest path through the network to the project completion point, considering the schedule model rules.

Key CPM Terms

CPM Calculation Logic

For a simple finish-to-start network using the same calendar:

\[ EF = ES + Duration \]\[ LS = LF - Duration \]\[ Total\ Float = LS - ES = LF - EF \]\[ Free\ Float = Earliest\ Successor\ ES - Activity\ EF \]

In real schedule software, calendars, relationship types, lag, constraints, and data date rules can make the calculations less intuitive. For exam purposes, know the basic mechanics and then check whether the question adds special conditions.

Relationship Types and Logic Quality

Common Relationship Types

Lags and Leads

A schedule with many constraints, lags, open ends, or missing logic may calculate dates, but it may not be a credible CPM model.

Constraints and Milestones

Constraints restrict schedule calculations. They may be necessary, but they should be used carefully.

Constraint Review Table

Milestone Rules

• Contract milestones should be clearly coded and traceable.
• Internal milestones should support management decisions.
• A milestone should usually have zero duration.
• Milestones need predecessors and successors unless they are legitimate project start or finish points.
• A milestone with no logic may be a reporting marker, not a schedule control point.

Float: What Candidates Often Misread

Float is one of the most tested scheduling concepts because it is easy to misinterpret.

Total Float vs. Free Float

Float Decision Rules

1. Low float does not automatically mean high importance. It means limited time flexibility.
2. High float does not mean the work can be ignored. Interfaces, resources, and risk still matter.
3. Float is path-based. Delaying one activity can consume float for multiple downstream activities.
4. Negative float requires explanation. It usually points to an imposed date, delay, or recovery need.
5. Critical path can change after progress updates. Do not assume the baseline critical path remains critical.

Calendars and Date Interpretation

Calendars affect calculated dates and float. They are a frequent source of wrong answers because candidates calculate as if every day is a workday.

Calendar Types

Calendar Traps

• Two activities with the same duration can finish on different calendar dates.
• Float may be calculated using successor calendars or project calendar rules depending on software settings.
• Weekend, holiday, and shift assumptions can change criticality.
• A milestone on a nonwork day may behave differently depending on calendar assignment.
• Comparing schedules requires checking whether calendars changed.

Baselines, Updates, and Forecasting

A baseline is the approved schedule used for comparison. Updating is the process of incorporating actual progress and forecasting remaining work.

Baseline vs. Current Schedule

Proper Update Sequence

    flowchart TD
	    A[Set status/data date] --> B[Enter actual starts and finishes]
	    B --> C[Update remaining durations]
	    C --> D[Record percent complete or physical progress]
	    D --> E[Review out-of-sequence work]
	    E --> F[Recalculate schedule]
	    F --> G[Analyze critical and near-critical paths]
	    G --> H[Compare to baseline]
	    H --> I[Report variance and forecast]

Update Quality Checks

Percent Complete and Progress Measurement

Progress measurement should match the type of work. A schedule update becomes unreliable when percent complete is subjective or inconsistent.

Common Progress Methods

Key Distinction

Percent complete and remaining duration are not the same.

An activity may be 80% complete but still have substantial remaining duration if the remaining work is difficult, constrained, or awaiting approval. Conversely, an activity may be 30% complete but close to finishing if early progress measurement was conservative.

Earned Value and Schedule Performance Links

The PSP exam may expect familiarity with how schedule information connects to project controls and performance measurement.

Core Earned Value Terms

Common formulas:

\[ SV = EV - PV \]\[ SPI = \frac{EV}{PV} \]

Interpretation Rules

Earned value schedule indicators do not replace CPM analysis. A project can have favorable earned value metrics and still be late if critical path work is delayed.

Resources, Productivity, and Leveling

Schedules should be achievable with available resources. Resource loading connects work quantities and productivity assumptions to durations.

Resource Concepts

Leveling Decision Rules

A common mistake is assuming more resources always shorten the schedule. In practice, congestion, limited workfaces, rework, supervision limits, and procurement constraints can reduce productivity.

Schedule Compression

Schedule compression attempts to shorten the project duration. It usually increases cost, risk, or coordination burden.

Compression Methods

Compression Exam Trap

If asked for the best compression option, first identify the critical path. Compressing noncritical work does not shorten the project unless it becomes critical or affects a controlling interface.

Schedule Risk and Uncertainty

A deterministic CPM schedule uses fixed durations, but real projects contain uncertainty. Schedule risk analysis evaluates the likelihood of different completion outcomes.

Risk Review Points

Risk Traps

• Do not treat CPM completion date as guaranteed.
• Do not bury all contingency in activity durations without transparency.
• Do not ignore near-critical paths.
• Do not assume the longest deterministic path is always the highest-risk path.
• Do not confuse risk response planning with after-the-fact delay analysis.

Delay Analysis and Forensic Scheduling

Delay analysis determines how events affected schedule completion or interim milestones. The key issues are usually causation, timing, criticality, concurrency, and entitlement under the applicable contract framework.

Common Delay Analysis Concepts

Delay Analysis Decision Questions

1. What was the controlling critical path before the event?
2. Did the event affect a critical or near-critical activity?
3. Did the event consume float or delay completion?
4. Was there concurrent delay?
5. Are the records contemporaneous and reliable?
6. Did the schedule update accurately reflect actual progress?
7. Was the delay caused by the event, or by unrelated performance issues?
8. What does the contract require for notice, documentation, and analysis?

Avoid jumping from “an event occurred” to “the project was delayed.” The exam often expects you to connect the event to critical path impact.

Schedule Quality Review

A schedule can look detailed but still be weak. Quality review focuses on whether the model is logical, complete, maintainable, and useful for control.

Schedule Quality Checklist

Common Schedule Defects

• Open-ended activities with no predecessor or successor.
• Excessive use of start-to-start relationships with large lags.
• Negative lags used to force overlap.
• Constraints used instead of logic.
• Progress entered without remaining duration review.
• Activities with actual dates in the future.
• Forecast dates before the status date.
• Missing long-lead procurement.
• Ignoring testing, turnover, commissioning, or owner approvals.
• Out-of-sequence progress not analyzed.

Contract, Change, and Schedule Control

The exam may frame scheduling within a project controls environment. Know how schedule control supports change management.

Change Control Schedule Questions

Baseline Change Trap

Not every variance justifies a new baseline. A baseline should generally be changed only through an approved process, such as authorized scope change, major approved resequencing, or other accepted project control procedure. Routine poor performance should be shown as variance, not erased.

Reporting and Communication

A scheduler must communicate schedule status clearly to project stakeholders.

Useful Schedule Reports

Good Reporting Practice

• Separate facts, forecasts, assumptions, and recommendations.
• Explain causes of variance, not just date movement.
• Identify critical and near-critical work.
• Show what changed since the last update.
• Make recovery actions specific and accountable.
• Avoid overloading executives with raw activity lists.

Ethics and Professional Judgment

Professional scheduling requires objectivity, transparency, and sound judgment. The exam may present scenarios where the technically correct answer also requires ethical handling of schedule information.

Ethical Risk Areas

A credible scheduler does not simply produce favorable dates. The scheduler produces defensible information for decision-making.

Calculation Quick Review

Forward and Backward Pass

For simple exam networks:

1. During the forward pass, calculate early dates from project start to finish.
2. During the backward pass, calculate late dates from project finish back to start.
3. Total float is the difference between late and early dates.
4. The critical path usually has the lowest total float.
5. If a required finish date is earlier than the calculated finish, negative float may appear.

Duration and Productivity

If a work quantity and productivity rate are provided:

\[ Duration = \frac{Quantity}{Production\ Rate} \]

If crew size affects total production:

\[ Duration = \frac{Quantity}{Crew\ Size \times Productivity\ per\ Crew\ Unit} \]

Check units carefully. Hours, shifts, calendar days, and workdays are not interchangeable.

Schedule Variance and SPI

\[ SV = EV - PV \]\[ SPI = \frac{EV}{PV} \]

Interpret earned value results together with CPM. A value-based schedule variance does not automatically equal a day-for-day delay to project completion.

Common Exam Traps

Conceptual Traps

Calculation Traps

• Forgetting to include lag.
• Ignoring relationship type.
• Treating calendar days as workdays.
• Choosing the path with the most activities instead of the longest duration.
• Calculating free float as if it were total float.
• Missing negative float caused by an imposed finish date.
• Not recalculating after a progress update.
• Rounding productivity or duration too early.
• Comparing baseline and current dates without checking scope changes.

Fast Review Tables

Best Action by Scenario

Schedule Document Review

How to Use Practice Questions After This Review

After reading this Quick Review, move into active practice. The fastest improvement usually comes from answering original practice questions, then studying detailed explanations carefully.

Recommended Practice Sequence

1. CPM foundations drill Practice forward pass, backward pass, float, relationship types, lags, and constraints.

2. Schedule development drill Work questions on WBS, activity definition, calendars, milestones, coding, and baseline quality.

3. Updating and control drill Focus on status date, actuals, remaining duration, progress measurement, and variance.

4. Resources and risk drill Review resource loading, leveling, productivity, contingency, and schedule risk concepts.

5. Delay analysis drill Practice identifying critical path impact, concurrent delay, fragnets, and reliable records.

6. Mixed mock exam set Combine calculations, judgment questions, and scenario-based scheduling decisions.

What to Review in Explanations

When using a question bank, do not stop at whether your answer was right. For each missed or uncertain question, identify:

• The scheduling concept being tested.
• The decision rule you missed.
• Any calculation setup error.
• Any keyword that changed the answer.
• Whether the issue was planning, CPM, updating, risk, resources, or delay analysis.
• How you would recognize the same concept in a different scenario.

Final Readiness Checklist

Before attempting a full mock exam, make sure you can confidently:

• Explain the difference between planning and scheduling.
• Build a logical activity network from scope and WBS.
• Calculate and interpret early dates, late dates, total float, and free float.
• Identify the critical path and near-critical paths.
• Recognize the effect of calendars, lags, constraints, and milestones.
• Update a schedule using actuals, remaining durations, and a status date.
• Compare current schedule forecasts to the baseline.
• Interpret schedule variance without confusing it with CPM delay.
• Evaluate resource loading and leveling impacts.
• Choose appropriate schedule compression methods.
• Understand risk, contingency, and uncertainty in schedule forecasts.
• Analyze delay using causation, criticality, timing, and documentation.

Practical Next Step

Use this Quick Review as your checklist, then move into PM Mastery practice with topic drills, original practice questions, mock exams, and detailed explanations. Focus first on CPM logic, float, updating, and delay-analysis scenarios, because those areas often reveal whether you truly understand professional planning and scheduling judgment.

Continue in PM Mastery

Use this Quick Review as a final concept map, then move into PM Mastery for focused topic drills, mixed practice sets, timed mock exams, and detailed explanations. The practice questions are original PM Mastery practice items; they are not official AACE questions, copied live-exam content, or exam dumps.