Scheduling options
Last reviewed 9 September 20261,733 words8 min read
The settings dialog that changes your dates
🟩 In one line: Tools → Schedule → Options holds a dozen settings that move dates and float without touching logic; agree them once, record them in the SBM, screenshot them into every submission, and check them on every XER you receive — because a file scheduled with different options is a different schedule.
👤 Who this is for: J/M. Reference page. Read with retained-logic-vs-progress-override and calendar-on-relationship-lag, which cover the two biggest settings in depth.
First, let's be honest about why this page exists
Two planners open the same XER, press F9, and get completion dates eleven days apart. Nothing in the file is different. One has Progress Override, Longest Path and lag on the successor calendar; the other has Retained Logic, float ≤ 0 and lag on the predecessor. Both are "right" according to their dialog.
This page is the dialog, one row per setting, with the recommended value and why. Owner note: field names follow P6 Professional 20-ish; verify against the version in use.
🟨 The standard — what "good" looks like
| Source | What it says (paraphrased) |
|---|---|
| P6 Professional User Guide — Schedule Options | Defines each option; notes that options are stored per user and per project and that changing them changes calculated dates. |
| AACE International RP 38R-06, Documenting the Schedule Basis | Scheduling software settings are part of the schedule basis and must be recorded. |
| AACE International RP 29R-03, Forensic Schedule Analysis | The analyst must establish and disclose the calculation settings used; results are not comparable across settings. |
| DCMA 14-Point — Metric 12 | Critical path test presupposes Longest Path or equivalent definition of critical. |
| GAO Schedule Assessment Guide — Best Practice 6 | The critical path must be calculated consistently and the method documented. |
| SCL Protocol, 2nd ed. — Part B, programme requirements | The programme's calculation settings should be agreed between the parties and held constant through the project. |
🟢 Rule: agree the options at baseline, record them in the SBM, do not change them without a recorded reason, and check the received file's options before you comment on its dates.
How it actually works
General tab — Tools → Schedule → Options
| Setting | Options | Recommended | Why | Effect if wrong |
|---|---|---|---|---|
| Ignore relationships to and from other projects | Tick / untick | Untick on a linked-project programme; tick when scheduling one project in isolation | Inter-project links are real logic | Ticked on a linked programme: external successors vanish, float inflates |
| Make open-ended activities critical | Tick / untick | Untick for reporting; tick during review to expose open ends | Ticked, every activity with no successor shows zero float | Ticked in a submission: critical path filter fills with dangles |
| Use Expected Finish Dates | Tick / untick | Tick if Expected Finish is used at all; otherwise irrelevant | Expected Finish recalculates remaining duration | Unticked: Expected Finish entries are silently ignored |
| Schedule automatically when a change affects dates | Tick / untick | Untick | Auto-reschedule mid-edit hides which change did what | Ticked: dates move while you type; no audit trail |
| Level resources during scheduling | Tick / untick | Untick | Levelling is a separate, deliberate step | Ticked: dates move by resource availability; float meaningless |
| Recalculate assignment costs after scheduling | Tick / untick | Tick if cost-loaded | Keeps cost aligned to dates | Unticked on a cost-loaded job: cash flow stale |
| When scheduling progressed activities use | Retained Logic / Progress Override / Actual Dates | Retained Logic | Preserves the network on out-of-sequence work; contractual default | Progress Override: out-of-sequence successors float free; forecast shortens without basis |
| Calculate start-to-start lag from | Early Start / Actual Start | Actual Start | Lag measured from when the predecessor really began | Early Start: SS successors can be scheduled before the predecessor actually started |
| Define critical activities as | Total Float ≤ n / Longest Path | Longest Path | Immune to multi-calendar float distortion | Float-based on a multi-calendar job: broken critical path |
| Calculate float based on finish date of | Each project / Opened projects | Each project for submissions; Opened projects for a portfolio view | Float against the project's own completion | Opened projects: float measured to the latest-finishing project in the group |
| Compute Total Float as | Start Float / Finish Float / Smallest | Finish Float | Matches the contractual test (delay to completion) | Smallest: mixed values on activities with SS/FF logic; confusing in review |
| Calendar for scheduling relationship lag | Predecessor / Successor / 24-hour / Project default | Predecessor | Lag follows the activity it hangs off | 24-hour: a 3-day lag on 6-day logic spans the weekend; dates shift |
Advanced tab
| Setting | Recommended | Why |
|---|---|---|
| Calculate multiple float paths | Untick for routine updates; tick for near-critical analysis | Adds Float Path and Float Path Order columns; slows scheduling on large files |
| Calculate based on | Free Float | Identifies driving chains better than Total Float on multi-calendar jobs |
| Display multiple float paths ending with activity | The contractual completion milestone | Paths measured to the date that matters |
| Specify number of paths | 5–10 | Enough to see the second and third paths; more is noise |
Related settings outside this dialog
| Setting | Path | Recommended |
|---|---|---|
| Critical float threshold | Project → Details → Settings → Critical activities have float less than or equal to | 0 |
| Data date | Project → Details → Dates | Set in the Schedule dialog, not here; same day each month |
| Hours per time period | Admin → Admin Preferences → Time Periods → Use assigned calendar | Ticked |
| Duration type default | Admin → Admin Preferences → General | Fixed Duration & Units |
| Schedule log | Tools → Schedule → Log to file | Ticked every run; read it |
The check on a received file. Open in the sandbox, Tools → Schedule → Options, screenshot, compare to the SBM table. If they differ, schedule once under their settings (record the dates), once under the agreed settings (record the dates), and put both in the review comment. The dates you compare against the baseline are the ones under the agreed settings.
🟥 Where people go wrong
- Not knowing options are per user. Your colleague opens your file and gets different dates. The SBM screenshot is what everybody sets before they press F9.
- Progress Override "because it gives a better date". It gives a shorter date by ignoring logic you haven't removed. On a contractual update it is indefensible.
- Leaving Make open-ended critical ticked in a submission. Every dangle is now on the critical path and the reviewer thinks the network is a mess. Use it to find dangles, then untick.
- Float ≤ 0 on a multi-calendar job. The critical path breaks at every calendar boundary. Longest Path.
- Changing an option to fix a problem. Switching lag calendar to fix one lag changes every lag in the file. Fix the lag.
- No screenshot in the transmittal. The Engineer's planner schedules under different options, gets a different date, and rejects the update for "not matching the narrative".
⚖️ When you're challenged
"We opened your file and completion is eleven days earlier than your narrative says." Check Tools → Schedule → Options against the table in the SBM, section 9 — Retained Logic, Longest Path, lag on predecessor calendar. The eleven days is Progress Override on the out-of-sequence MEP work; under the agreed settings the date matches the narrative. Screenshot of our dialog is on page 2 of the transmittal.
"Why not Progress Override? It reflects what's actually happening." It reflects the crew being out of sequence and assumes they can carry on that way indefinitely. Retained Logic keeps the successors behind the predecessors that haven't finished. If the logic is genuinely no longer needed, I'll change the relationship and record it — not the calculation setting.
"Can you switch to Smallest float so the SS activities read properly?" Finish float is the contractual test — delay to completion. Smallest float gives mixed readings on SS pairs that confuse the narrative. The SS activities are fine under Longest Path; I'll add the Float Path column if that helps.
📄 Related pages
- Retained logic vs progress override — the biggest setting, in depth.
- Calendar on Relationship Lag — the second biggest.
- Critical path vs longest path — the Define Critical setting.
- P6 Multiple Float Paths — the Advanced tab.
- P6 Settings That Change Your Dates — every other setting outside this dialog.
- Schedule Basis Memorandum — where the options table lives.
- Cleaning an XER Before Import — checking a received file.
✏️ Worked example
A data centre in Abu Dhabi, Update 10. The Engineer's planner reports completion 14 March; the contractor's narrative says 25 March. Same XER.
| Setting | Engineer's dialog | Contractor's dialog (SBM) | Date effect |
|---|---|---|---|
| Progressed activities | Progress Override | Retained Logic | −8 working days (containment installed out of sequence on L2; PO releases cable pull) |
| Define critical | Total Float ≤ 0 | Longest Path | No date effect; critical path display differs |
| Lag calendar | 24-hour | Predecessor | −3 working days (curing lags on 6-day logic spanned weekends) |
| Total float | Smallest | Finish | No date effect; float column differs |
Combined: 11 working days. Resolution: the Engineer's planner adopted the SBM settings; both sides logged the options table in the review minutes; the transmittal template gained a dialog screenshot.
📖 References
- Oracle Primavera P6 Professional User Guide — Schedule Options, General and Advanced tabs; Project Details, Settings; Admin Preferences.
- AACE International RP 38R-06, Documenting the Schedule Basis.
- AACE International RP 29R-03, Forensic Schedule Analysis.
- DCMA 14-Point Schedule Assessment — Metric 12.
- GAO-16-89G, Schedule Assessment Guide — Best Practice 6.
- Society of Construction Law, Delay and Disruption Protocol, 2nd ed. (2017) — Part B.
From the field
Experience from working planners. Unreviewed — read it as experience, not guidance.
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