Learning Center
How to Read a Primavera Baseline Schedule Report
A Primavera P6 baseline report looks like a wall of numbers the first few times you open one. It isn’t — every column and warning has a specific job. Here’s what each part means, using a small example project, plus the built-in warnings that quietly do a lot of the same work as a formal schedule health check.
What “Baseline” Actually Means
A baseline is a saved snapshot of the schedule as planned, taken before work starts: every activity’s original duration, logic, and dates, frozen in place. It exists so that every later update has something fixed to compare against — without a baseline, “are we behind?” has no honest answer, because there’s nothing to be behind from.
Because nothing has happened yet on a baseline, a few fields are predictable in a way they won’t be once the project is underway: Remaining Duration equals Original Duration for every activity, Actual Duration is zero, and percent complete is 0% across the board. That’s normal — it’s what makes a baseline a baseline.
A Small Example Project
Here’s a simplified baseline for a fictional pump station upgrade — nine activities, one critical path, and one activity with a bit of breathing room. Diamonds are milestones (zero duration); boxes are activities, labeled with ID and duration in days.
| Activity ID | Activity Name | OD | ES | EF | LS | LF | TF |
|---|---|---|---|---|---|---|---|
| 1000 | Notice to Proceed | 0 | 0 | 0 | 0 | 0 | 0 |
| 1010 | Mobilize & Site Setup | 5 | 0 | 5 | 0 | 5 | 0 |
| 1020 | Demo Existing Pump Equipment | 8 | 5 | 13 | 5 | 13 | 0 |
| 1030 | Electrical Rough-In | 10 | 13 | 23 | 17 | 27 | 4 |
| 1040 | Install New Pumps | 12 | 13 | 25 | 13 | 25 | 0 |
| 1050 | Piping & Valve Installation | 9 | 25 | 34 | 25 | 34 | 0 |
| 1060 | Instrumentation & Controls | 7 | 25 | 32 | 27 | 34 | 2 |
| 1070 | Testing & Commissioning | 6 | 34 | 40 | 34 | 40 | 0 |
| 1080 | Substantial Completion | 0 | 40 | 40 | 40 | 40 | 0 |
| 1090 | Project Complete | 0 | 42 | 42 | 42 | 42 | 0 |
A 2-day administrative closeout lag sits between Substantial Completion and Project Complete, which is why the finish jumps from day 40 to day 42.
Critical path: 1000 → 1010 → 1020 → 1040 → 1050 → 1070 → 1080 → 1090, a 42-day duration. Electrical Rough-In (1030) and Instrumentation & Controls (1060) both have float — they can slip a few days without moving the finish date, because Install New Pumps and Piping & Valve Installation together already take longer than either of them.
What Each Column Is Actually Telling You
- Activity ID
- A unique reference number. Numbering gaps (1000, 1010, 1020…) are deliberate — they leave room to insert new activities later without renumbering everything.
- OD / RD / AD (Original / Remaining / Actual Duration)
- OD is the planned length. Once work starts, RD counts down and AD counts up as progress is reported; on a baseline, RD = OD and AD = 0 for everything.
- % Complete
- Progress reported against that activity, always 0% on a baseline.
- ES / EF and LS / LF
- The same forward-pass and backward-pass dates covered in our critical path method example — the earliest and latest an activity can start and finish without delaying the project.
- TF (Total Float)
- The gap between the early and late dates. Zero means the activity sits on the critical path.
The Warnings Section Is Doing a Health Check For You
Before a P6 report even gets to the activity list, it runs a set of automatic checks and flags anything unusual. These aren’t cosmetic — they’re an early version of the same logic checks a formal DCMA 14-point assessment performs.
| Warning | What it’s actually flagging |
|---|---|
| Activities without predecessors | An activity with nothing driving its start date. Aside from the project's true first activity, this usually means a missing logic tie — the activity can float freely in a way that doesn't reflect reality. |
| Activities without successors | The mirror image: nothing depends on this activity finishing. Aside from the project's true last activity, it's often a sign the schedule never got tied back into the rest of the network. |
| Out-of-sequence activities | Work reported as started or progressing before its predecessor actually finished — the field reality has moved ahead of what the schedule's logic says should happen next. |
| Activities with actual dates > data date | Progress dated in the future relative to the schedule's own as-of date — usually a data-entry problem, but one that quietly throws off every downstream calculation. |
| Milestone activities with invalid relationships | A milestone tied to predecessors on a different calendar or with conflicting logic, which can make its calculated date meaningless. |
This is exactly what automated health checks are built for. Claims Digger runs a full DCMA 14-point assessment on real P6 schedules automatically, catching these logic issues (and more) across thousands of activities instead of a handful. See how it works.
Frequently Asked Questions
- What is a baseline schedule in Primavera P6?
- The baseline is the schedule version saved before work starts, representing the original planned sequence, durations, and dates. Every later update gets compared back to it to measure progress and identify delay.
- What do OD, RD, and AD mean on a P6 schedule report?
- OD is Original Duration, the activity's planned length. RD is Remaining Duration, how much work is left. AD is Actual Duration, how long the activity has actually taken so far. On a baseline report, RD equals OD and AD is zero because no work has started yet.
- What does it mean if an activity has no predecessor or successor?
- It means that activity isn't logically tied to the rest of the network on that side, so P6 can't calculate a reliable early or late date for it. Aside from the true first and last activities in a schedule, this is usually a sign of missing logic and is one of the checks in a DCMA 14-point health assessment.
- What is an out-of-sequence activity?
- It's an activity that started or progressed before its predecessor finished, out of order with the schedule's own logic. A schedule with a lot of out-of-sequence activities is a sign the logic no longer reflects how the work is actually happening.
- Why do schedule report warnings matter for delay claims?
- A schedule full of logic problems produces an unreliable critical path, and an unreliable critical path undermines any delay analysis built on it. Courts and reviewing agencies increasingly expect these health checks to have been done before a schedule is relied on for a claim.
Part of the Claims Digger Learning Center. Read more: Part 2: Reading a baseline like a forensic analyst · Critical path method example · Legal significance of the schedule · Full glossary