AACE International PSP - Planning & Scheduling Professional (PSP) Exam

Activities not on the critical path are those with positive float, meaning they can be delayed without affecting the overall project completion time. The determination of such activities requires performing a forward and backward pass calculation as per CPM (Critical Path Method) analysis principles (PSP Study Guide, Section 2.2.4, "Relationships").

For example:

Identify the critical path by analyzing total float values (typically, critical path activities have zero total float).

Exclude activities that do not fall on the critical path.

ï‚· Assumptions in Planning:

Assumptions are placeholders until verified facts are available. Replacing them enhances schedule reliability and accuracy.

ï‚· Evaluation of Other Options:

A: Shifting risks is not a proactive solution.

C: Sole reliance on experience without verification is risky.

D: Internal memos clarify assumptions but do not replace facts.

ï‚· Verification with PSP Guidelines:

PSP emphasizes validating assumptions during the planning phase (Ref: PSP Study Guide, Chapter 1B: Planning Fundamentals).

ï‚· Key to Duration Accuracy:

A specialized industry handbook offers standardized and validated task durations tailored to the specific context of petrochemical plants.

ï‚· Analysis of Options:

Option A: General industry publications may lack specificity.

Option B: Past project schedules provide insight but may not reflect the specific context or updated methodologies.

Option C: The handbook is most relevant as it is tailored to the specific project type.

Option D: Cost estimates are useful for budget alignment but not as precise for duration calculation.

ï‚· PSP Study Guide References:

The guide advises leveraging validated industry resources for project-specific accuracy in duration estimation​.

ï‚· Conclusion: The correct answer is C, as a specialized industry handbook provides the most reliable and context-specific data for duration estimation.

ï‚· Construction Life Cycle Phases:

Common phases: planning and design, installation (execution), and turnover/start-up.

Claims and disputes may arise during the project but are not a defined phase of the construction life cycle.

ï‚· PSP Study Guide References:

The study guide outlines standard phases without including claims and disputes as a formal phase​.

ï‚· Conclusion: The correct answer is A, as claims and disputes are not an inherent phase of the construction life cycle.

ï‚· Early Start Constraint:

An early start constraint specifies the earliest date on which an activity can begin, aligning with project constraints or milestones.

It is a planning input and does not dictate actual or remaining durations.

ï‚· PSP Study Guide References:

Scheduling constraints, including early start, are critical for establishing realistic schedules and milestones​.

ï‚· Conclusion: The correct answer is C, as an early start constraint refers to the planned start date of an activity.

ï‚· Understanding the Problem Context:

Activity C is currently set to complete on Day 40.

Activity A has a 5-day delay in starting, so adjustments are needed to maintain the Day 40 completion date for Activity C.

The key is to identify which adjustment will fail to maintain the timeline.

ï‚· Option-by-Option Analysis:

A. Reduce the duration of 'A' from 20 days to 10 days and replace the relationship from 'B' to 'C' with FSO (Finish-to-Start with Offset):

Reducing Activity A’s duration from 20 to 10 days might mitigate part of the delay, but replacing the relationship between B and C with FSO introduces an offset.

FSO relationships typically delay the start of successor activities (Activity C in this case).

This would likely push Activity C beyond Day 40 because the delay in B's finish, coupled with the offset, would result in C starting later.

This adjustment does NOT maintain the completion date of Activity C.

B. Replace the relationship from 'B' to 'C' with SSO (Start-to-Start with Offset):

An SSO relationship allows Activity C to begin once Activity B starts (with or without an offset).

This adjustment effectively overlaps the schedules of B and C, mitigating delays from A.

This adjustment can maintain the completion date of Activity C at Day 40.

C. Reduce the duration of 'B' from 10 days to 5 days by compressing work effort:

Reducing B’s duration by compressing its schedule shortens its timeline, allowing Activity C to start sooner.

This adjustment offsets the delay caused by Activity A.

This adjustment can maintain the completion date of Activity C at Day 40.

ï‚· Final Answer and Justification:

The adjustment described in A will NOT maintain the completion date of Activity C at Day 40 because the FSO relationship introduces delays, making it ineffective in this scenario.

Options B and C offer feasible adjustments to maintain the timeline.

ï‚· Study Guide Reference:

Refer to the PSP Certification Study Guide, Chapter 2 – Scheduling, Subchapter 2.2.4: Relationships (p. 151-157), which details the impact of logical relationships (FSO, SSO) on schedule timelines.

Additionally, review AACE Recommended Practice 52R-06: Time Impact Analysis for insights into how delays affect dependent activities and methods for mitigating them.

ï‚· Determining the Late Finish (LF) of Activity 6002 involves analyzing its successor activity, 6003, and considering the lag (if any).

ï‚· By subtracting 1 day from the Late Start (LS) of 6003, the Late Finish (LF) of 6002 is derived. The date calculation aligns with this logic, making 09 Mar 2023 the correct date.

 References: PSP Study Guide, Section 2.2.5 – Constraints and Calendars, and Appendix A – Example CPM Problems, which detail LF and LS calculations.

The time an activity can be delayed from its early start without impacting the overall project completion date is called total float.

Option A (negative float) refers to delays beyond permissible limits.

Option B (free float) refers to delays without affecting the early start of any successor.

Option D (interfering float) is a lesser-used term denoting the time available without delaying the project completion but affecting a successor’s float​.