Grouping and sorting

A contractor's schedule can hold 600 activities, and the order you see them in is not neutral. Grouping decides which bands the activities fall into; sorting decides their order inside each band. The same Oracle Primavera P6 file can read as the contractor's work breakdown or the owner's milestone story without a date changing. This lesson shows how the Group and Sort dialog works and how an owner uses it to review a baseline quickly and honestly.

Learning outcomes

• Open the Group and Sort dialog in P6 Professional and group activities by WBS, by a field or by an activity code.
• Set the sort order inside groups and explain why P6 always groups first and sorts second.
• Use group intervals, Show Summaries Only, Show Grand Totals, Hide if empty and group page breaks to build a review-ready view.
• Set up owner review groupings for a contractor baseline without touching the contractor's data.

The lesson

Group first, then sort

Grouping organizes activities into bands that share a value, such as a WBS element, a department, a responsible person, a date range or a total float range [1]. Sorting arranges activities in order chronologically, alphabetically, numerically or by hierarchy [2]. When a layout uses both, P6 groups first and then sorts within each group [1][2]. That rule explains most surprises: if you sort by Start and the earliest activity is not at the top of the screen, it is because it sits in a later band.

Both settings live in one place. In P6 Professional, choose Project, Activities, then View, Group and Sort By [3]. The dialog's Default button puts the layout back to grouping and sorting by WBS code [4], which is where most imported XER files start. Grouping and sorting are saved with the layout, so a saved owner layout (see Lesson 16) brings its bands back every time you open it.

What you can group by

In the Group By section, click a cell and choose a field; repeat to add levels, up to 20 [3]. Useful fields for schedule review include WBS, Activity Type, Calendar, Primary Resource, Start, Finish, Total Float and any activity code. Activity codes are the owner's best friend here: a code such as "Area" or "Responsibility", set up in Lesson 15, cuts across the WBS and answers questions the WBS cannot.

Some fields are hierarchical: the EPS, OBS, WBS and cost accounts, for example [5]. For these, P6 marks Indent automatically, and To Level sets how many levels of the hierarchy to show as bands [4][5]. Group by WBS with To Level set to 2 and a deep WBS collapses into its top two levels. If you look after several projects that share one WBS structure, grouping by WBS Path lines up identical WBS levels across projects without showing the project node [6].

Figure 1 maps the dialog. It is a diagram of the controls, not a screenshot.

Group intervals: banding dates and numbers

Grouping on a date or a number without an interval gives one band per value, which is rarely useful. The Group Interval column fixes that. For date fields you choose Day, Week, Month, Quarter or Year; for numbers you type a step. Oracle's own example groups by Remaining Duration with an interval of 5d, which produces bands of 0 to 5 days, 5 to 10 days and so on [4]. Group by Finish with a Month interval and you have a "what finishes when" view. Group by Total Float with a 5d interval and you can see in seconds how much of the job sits within a week of the critical path.

Sorting inside the bands

To sort, open the dialog, click Sort, then Add, choose a field in the Field Name column and set the Sort Order to ascending, descending or hierarchical. Add more rows for tie-breakers, click OK, and use Apply to preview [7]. Hierarchical only appears for hierarchical fields such as WBS or Responsible Manager [2].

Know how each data type sorts [2]:

• Dates sort chronologically, earliest first when ascending.
• Numbers sort from the largest negative to the largest positive when ascending. Sort Total Float ascending and negative float comes first, which is what a reviewer wants.
• Codes and text sort alphanumerically, 0 to 9 and then A to Z, when ascending. In practice the comparison runs character by character, so an activity ID like A900 lands after A1000. Contractors who number activities in fixed-length IDs avoid this.

Figure 2 shows the group-then-sort rule on six Northgate activities from Lesson 7.

View the data

Band (Activity Type)	Activity	Start	Finish
Start Milestone	M3 Site mobilization	Mon Mar 1, 2027	None
Task Dependent	3.1 Footings & piers	Mon Mar 15, 2027	Fri Apr 9, 2027
Task Dependent	3.2 Slab-on-grade	Mon Apr 12, 2027	Fri May 14, 2027
Level of Effort	QC & testing, foundations	Mon Mar 15, 2027	Fri May 14, 2027
WBS Summary	WBS 3 summary	Mon Mar 15, 2027	Fri May 14, 2027
Finish Milestone	M4 Foundations & slab complete	None	Fri May 14, 2027

Summaries, totals and empty bands

Three checkboxes turn a long list into a summary. Show Summaries Only shows the bands and hides the activities under them [4][8]. Show Grand Totals adds a total row at the top of the layout [4][9]. Show Group Totals puts totals in each band [4]. Group by WBS to level 2 with summaries only and the whole Northgate job fits on one screen.

Hide if empty hides bands with no activities in them [10]. Oracle recommends it when you group by a hierarchy such as the WBS and the project has empty WBS elements, because hiding the empty bands keeps the rolled-up data accurate [4]. Leave it off when you are checking structure: an empty band is a WBS element the contractor created and never used, and that is worth asking about.

The band label itself is configurable. Double-click Font & Color to change the text and fill, and use Show Title, Show ID/Code and Show Name/Description to decide whether a band reads "WBS: 3 Foundations & slab-on-grade" or just "3" [11].

Page breaks by band, and removing groups

Mark Page Break on a group row and each band of that level starts a new printed page. The breaks show only in Print Preview and in published layouts, and they are saved with the layout [12]. Lesson 20 uses this for the owner's print pack. To take a level out, select it in the Group By column and click Delete [13].

Screenshot to come

Northgate worked example

Northgate Distribution Centre (fictional) is a 12,000 m² tilt-up warehouse in Vaughan, Ontario, built by Halvorsen Builders Ltd. (fictional) for Northgate Logistics Inc. (fictional) under a CCDC 2-2020 stipulated price contract (see the Northgate fact sheet). Halvorsen's baseline XER has been imported as NDC-BL00 into the owner's NDC.SUB branch. The owner's scheduler never edits the contractor's groupings. Instead she builds owner layouts, each answering one question, and saves them under the owner's name so they survive every update.

Five questions, five groupings

Figure 3 is the set she uses on every submission. None of them changes a date. Each one changes what the reader sees first.

What the groupings find

On NDC-BL00 the Activity Type view is the milestone roll call: M3 and M8 in the Start Milestone band, M4 to M7, M9 and M11 in the Finish Milestone band, each once (M0 to M2 and M10 live in the owner's Microsoft Project master, not the contractor's file). The WBS summary view should show ten bands matching the fact sheet's level 2 elements, from 1 Project management & pre-construction to 10 Closeout. With Hide if empty cleared, any extra empty band is a question for Halvorsen.

The float view is where the review starts. The scheduler groups by Total Float with a 5d interval and sorts by Total Float ascending, then Start. The first band holds the zero and negative float work, which on a baseline should be a single, readable chain toward M9 (Ready-for-Takeover / Substantial Performance, Fri Jan 14, 2028). A large first band tells her where to look next. Lessons 11 and 12 cover how to read what she finds.

The Responsibility view uses an activity code that the owner's specification asks Halvorsen to assign to every activity (codes are set up in Lesson 15). Grouped by that code and sorted by float, it shows which trade or party holds the tightest work, which is the conversation to have at the next schedule meeting.

Screenshot to come

Owner's move

• Review in your own layouts. Save the five groupings as owner layouts and open the contractor's file read-only. Never re-group the contractor's own layout and send it back.
• Require codes that make grouping possible. Put the activity codes you need, such as Area and Responsibility, in the schedule specification, with a rule that every activity carries a value.
• Ask for fixed-length activity IDs. Text sorts character by character, so mixed-length IDs scramble any sort by ID.
• Always look at the float view first. It is the fastest route to the critical path and to activities that should not be near it.
• Check for empty WBS bands, then hide them. Look once with Hide if empty off to find unused elements; turn it on for any view that shows roll-up totals.

Common mistakes

1. Expecting a sort to cross bands. Sorting by Start inside WBS bands does not give a chronological list. Remove the grouping, or group by Start with an interval.
2. Grouping on a date with no interval. The result is one band per day. Set Week or Month.
3. Reporting from Show Summaries Only. Summary bands hide the detail. A clean-looking summary is not a review.
4. Leaving empty bands in a totals view. Oracle's advice is to hide them when grouping by a hierarchy so roll-ups stay accurate [4].
5. Sorting text IDs as if they were numbers. A900 after A1000 is correct alphanumeric sorting, not a P6 bug.

Quick quiz

1. A layout is grouped by WBS and sorted by Start ascending. What does P6 do first?

   1. Sorts all activities by Start, then groups them
   2. Groups activities by WBS, then sorts within each band
   3. Applies whichever was set most recently
   4. Ignores the sort while a grouping is set

2. You group by Total Float and want bands of 0 to 5 days, 5 to 10 days and so on. Which setting do you use?

   1. To Level
   2. Indent
   3. Group Interval
   4. Shrink vertical grouping bands

3. Sorted ascending, which Total Float value appears first?

   1. 0d
   2. –10d
   3. 5d
   4. Blank values

4. Why does Oracle recommend Hide if empty when grouping by WBS?

   1. It speeds up scheduling
   2. It deletes unused WBS elements
   3. It keeps rolled-up data accurate
   4. It is required for page breaks

5. What does the Default button in the Group and Sort dialog do?

   1. Removes all grouping
   2. Groups and sorts by WBS code
   3. Restores the contractor's original layout
   4. Groups by Activity Type

Show answers and explanations

1. B. When both are used, items are grouped first and then sorted [1][2].
2. C. Group Interval bands numeric and date fields; Oracle's example is 5d on Remaining Duration [4].
3. B. Ascending numbers run from the largest negative to the largest positive [2].
4. C. Hiding empty WBS or EPS bands ensures rolled-up data is accurate [4].
5. B. Default applies the default grouping and sorting, by WBS code [4].

Key terms

Grouping band

A coloured row that collects activities sharing a value, such as a WBS element or activity code value.

Group Interval

The step used to band date or number fields, such as Month for dates or 5d for durations and float.

To Level

The number of hierarchy levels shown as bands when grouping by a hierarchical field such as the WBS.

Show Summaries Only

Shows grouping bands and hides the activities under them.

Hide if empty

Hides bands that contain no activities.

Hierarchical sort

Sorts codes in the order they sit in their hierarchy, available only for hierarchical fields.

WBS Path

A grouping that lines up identical WBS levels across projects without showing the project node.

References

1. Oracle. Grouping activities by field. Primavera P6 Professional Help, Version 26.
2. Oracle. Sorting. Primavera P6 Professional Help, Version 26.
3. Oracle. Group activities by field. Primavera P6 Professional Help, Version 26.
4. Oracle. Group and Sort dialog box. Primavera P6 Professional Help, Version 26.
5. Oracle. Grouping by hierarchy. Primavera P6 Professional Help, Version 26.
6. Oracle. Grouping activities by WBS path. Primavera P6 Professional Help, Version 26.
7. Oracle. Sort activities. Primavera P6 Professional Help, Version 26.
8. Oracle. Display summary data when grouping. Primavera P6 Professional Help, Version 26.
9. Oracle. Show a grand total. Primavera P6 Professional Help, Version 26.
10. Oracle. Show or hide empty title bands. Primavera P6 Professional Help, Version 26.
11. Oracle. Format grouping bands. Primavera P6 Professional Help, Version 26.
12. Oracle. Set Page Breaks by Group Band. Primavera P6 Professional Help, Version 26.
13. Oracle. Remove activity groupings. Primavera P6 Professional Help, Version 26.

Verified on November 6, 2026.

Next lesson in this trackBars and Gantt formatting