How to QA a Primavera P6 Schedule: A Practical Quality-Check Guide

Why Schedule Quality Matters Before You Accept an Update

Accepting a contractor's schedule update without a thorough schedule quality check is like signing off on a set of structural calculations without reviewing them. A poor-quality schedule can mask delays, misrepresent progress, and lead to costly disputes. A robust quality assurance (QA) process ensures the schedule is logically sound, accurately reflects the work, and is suitable for performance measurement and forensic analysis.

A schedule that fails basic quality checks can also trigger contractual penalties or undermine an extension of time (EOT) claim. By implementing a repeatable QA workflow, you protect your project and your organisation.

What to Check: The Core Elements of a Schedule Quality Check

1. Logic and Sequencing

Verify that every activity (except the first and last) has at least one predecessor and one successor. Missing links create open ends, which can cause inaccurate float calculations and unrealistic critical paths. Check for:

• Open ends: Activities without predecessors or successors (DCMA 14-point check #1).
• Lags and leads: Ensure they are justified and not masking poor logic.
• Constraint usage: Constraints like 'Must Finish By' or 'Start On' can override logic and should be minimised. DCMA recommends no more than 5% of activities with constraints (check #8).

2. Float and Critical Path

Total float (TF) indicates schedule flexibility. A schedule with excessive negative or positive float may indicate flawed logic or overly optimistic durations. Key checks:

• Negative float: If present, the schedule is behind. Ensure it is realistic and not caused by illogical constraints.
• Longest path: Verify that the critical path (TF ≤ 0) is continuous and makes sense.
• High float: Activities with very high float (> 44 days) may be disconnected from the main logic (DCMA check #7).

3. Durations and Calendars

Unrealistic durations are a red flag. Check for:

• Duration outliers: Very short (e.g., 1 day) or very long activities (e.g., > 100 days). DCMA suggests that no more than 5% of activities should have durations > 44 days (check #6).
• Calendars: Ensure each activity uses the correct calendar (e.g., 5-day vs 7-day) and that holidays are accounted for.
• Milestones: Should have zero duration. If not, they are not true milestones.

4. Resources and Costs

While not always required, resource-loaded schedules should be checked for:

• Over-allocation: Resources assigned to more work than available per calendar.
• Cost loading: Verify that total costs align with the budget and that cost distribution is logical.

DCMA / GAO / NASA Frameworks at a Glance

Several government and industry frameworks provide standardised schedule quality checks. Here’s a quick reference:

Each framework emphasises that a schedule must be a reliable tool for decision-making, not just a compliance document.

A Repeatable QA Workflow

Follow these steps for a consistent schedule quality check:

1. Import and review metadata: Check project start, data date, calendars, and WBS structure.
2. Run automated checks: Use tools like Project Assure to instantly run DCMA 14-point, GAO, and NASA checks. This free browser-based tool parses your XER locally—nothing is uploaded.
3. Analyse logic and constraints: Look for open ends, lags, and improper constraints.
4. Review float and critical path: Identify negative float and verify the longest path.
5. Check durations and calendars: Flag outliers and calendar mismatches.
6. Validate resource/cost loading (if applicable): Check for over-allocation and cost alignment.
7. Document findings: Create a QA report listing issues, severity, and recommendations.
8. Iterate with contractor: Discuss findings and request corrections before accepting the update.

By following this workflow, you ensure every schedule update meets a minimum quality standard, reducing risk and improving project control.

Remember, a schedule quality check is not a one-time event. Perform it at every major update (e.g., monthly) and always before a baseline change. Tools like Project Assure make this process fast and repeatable—ideal for busy schedulers and project controls teams.