1. Defining, Assessing and Managing
Critical & Near Critical Activities
using Primavera P6
Indra Pandu Prasetyo
With sample project schedule cases

2. 2
Content
Critical Activities Definition01
Near Critical Activities Definition and Why It Is Important02
Defining Multiple Critical Activities in Primavera P603
Assessing Critical Activities Reliability04
Managing Critical - Near Critical Activities05

3. 3
Critical Activities Definition
01

4. 4
Critical Activities Definition
According to Primavera P6, there are 2 options to define critical activities:
If project has several deadlines (constraints), this option is
useful to track the total float of each deadline
Longest path is useful to focus on sequences that
determine overall project completion, the amount of delay
in the longest path shall be equal to the amount of delay to
project completion
Longest path
Total float ≤ 0

5. 5
Critical Activities Definition
Schedule Options for critical activities definition in Primavera P6
By default, P6 will define critical activities as total float
less than or equal to zero
Both options will result same float number
All sample schedules in this material use “Total Float
less than or equal to 0” as critical activities definition,
simultaneously longest path is seen through activity
column
Alternative way to see longest path is by showing
“Longest Path” column in activity window

6. 6
Critical Activities Definition
Longest Path shall be Critical, but Critical is not always Longest Path
Show these columns in P6 to see critical and longest pathSample Schedule
Critical Sequence Critical Longest
1 M01 > DA1 > DB0 > PB0> M03 Yes Yes
This sequence is determining Project Finish date
at current state
2 M02 > PC0 > M03 Yes No
This sequence is critical because of constraint
on M03

7. 7
Critical Activities Definition
Simulation 1 - Delay on Longest Path sequences affect project completion date
DB0 duration changes from 15d to 20d (5 days longer)
M04 completion date changes from 30 Oct to 4 Nov (5 days shifted)
2
1
1
2
Sample Schedule – Simulation 1

8. 8
Critical Activities Definition
Simulation 2 - Delay on Critical may not affect project completion date if there is
gap available between end date of critical sequence and completion date
PC0 duration changes from 17d to 25d (8 days longer), but no impact to M04 completion
M03 shifts, affecting negative total float (-8 days) to M02-PC0-M03 due to constraint use on M03
M02 > PC0 > M03 is now longest path since the gap between M03 to M04 has been used up
2
1
2
1
Sample Schedule – Simulation 2

9. 9
Near Critical Activities Definition and Why It Is Important
02

10. 10
Near Critical Activities Definition and Why It Is Important
Near critical activities are activities that are close to becoming critical activities, it
can be defined as:
The terminology of “near to zero” may be different for every project, e.g. < 30d, <5% project duration
Activity with total float near to zero
Activity sequences that close to becoming longest path
Activities sequence that is near to longest path
It seems hard to determine near critical using CPM when the project approaches middle or final stage since
almost all remaining works may be close to critical
Expert opinions may be considered to determine its criticality regardless of the float value calculated
Near critical based on expert judgement

11. 11
Near Critical Activities Definition and Why It Is Important
Reasons why determining near critical activities is important:
It can be surprising when the non-critical activities are becoming critical after schedule updated, and by
identifying near critical activity, critical activities can be mitigated much earlier and resources can be
managed effectively
Managements often find difficulty in monitoring all activities other than critical ones, therefore identifying
the near critical activities can help managements to put their attention on too
Management often put less attention to non-critical activities
Critical activities may change as the project progressed

12. 12
Defining Multiple Critical Activities in Primavera P6
03

13. 13
Defining Multiple Critical Activities in Primavera P6
Primavera P6 has feature called “Calculate multiple float paths” that can group
activities sequence based on its float so near critical activities can be shown
11 Feature can be accessed in Schedule Options
Hit F9 > Options… > choose Advanced tab
2 2 Tick this to enable P6 calculating multiple float path
3
3 Choose the calculation method
 Total float : This will identify criticality by activity total
float
 Free float : This will identify criticality based on longest
path
4
5
4 Choose activity to set as end of float calculation, or leave it
blank to calculate float based on project finish date/
constraint
5 Set the number of float path
If 5 is entered, then it will calculate 5 most critical float
paths ending with activity selected or project finish

14. 14
Defining Multiple Critical Activities in Primavera P6
When calculate multiple float path option is enabled, P6 will calculate Float Path
and Float Path Order value
Show these columns to see float path calculation
Float Path : Group of activities based on its criticality, 1 means the most critical
Float Path Order : Activity sequence order for each float path
Schedule the project <F9> to re-calculate the float path value
Notes !
Calculating multiple float path doesn’t affect how critical activities (Critical or Longest Path) are defined, it can
be set separately through Schedule Options – General tab – Define critical activities as
Sample Schedule

15. 15
Defining Multiple Critical Activities in Primavera P6
Group the activities by Float Path, then Sort by Float Path Order to see the critical
and near critical activities in sequential group and order
Go to Group and Sort menu, and choose Float Path in Group By
Sample Schedule

16. 16
Defining Multiple Critical Activities in Primavera P6
Calculating multiple float path using Total Float generates float path value based
on activity total float
Float Path Sequence
1 Critical A1 > A2 > A3 > XA Total float is 0 and also the longest
2 Near Critical-1 B1 > B2 > B3 Total float is 0 due to constraint use on B3
3 Near Critical-2 C1 > C2 Total float is 2
Sample Schedule – The lowest total float will be the most critical

17. 17
Defining Multiple Critical Activities in Primavera P6
Calculating multiple float path using Free Float generates float path value based
on free float/ longest path
4d
Sample Schedule – The closer an activity sequence to the longest path, the more critical it will be
Float Path Sequence
1 Critical A1 > A2 > A3 > XA The longest path
2 Near Critical-1 C1 > C2 It has 2d gap before it becomes longest path
3 Near Critical-2 B1 > B2 > B3 It has 4d gap before it becomes longest path
2d

18. 18
Defining Multiple Critical Activities in Primavera P6
Calculating multiple float path using Total Float with ending on B3 is limiting the
float path calculation only to activities that linked to B3
Calculate multiple float path using Free Float will produce same result since there’s only one
sequence linked to B3
Float Path Sequence
1 Critical A1 > B1 > B2 > B3
Sample Schedule – There’s only one sequence in Float Path, since no other activities linked to B3
Float paths are not calculated

19. 19
Assessing Critical Activities Reliability
04

20. 20
Assessing Critical Activities Reliability
Followings are steps to prove critical activities reliability:
Healthy project schedule tends to have reliable critical activities
Check the schedule health
Longest path (critical path) should have continuous activities sequence from project start or data date to the
project completion
Check longest path continuity
The amount of delay for each activity on longest path/ critical path should be same with the delay on project
completion
Check longest path/ critical path integrity

21. 21
Assessing Critical Activities Reliability
Check the schedule health
Criteria to check Description
Missing logic/ open end All activities shall have at least an FS/SS predecessor and an FS/FF successors
Leads (negative lags) No lead (negative lags), convert lead to activity
Lags Minimize lags, convert lag to activity
Relationships Maximize FS logic, especially for critical sequences
Hard constraint Minimize using hard constraint
High total float Minimize activities with high total float, re-check the relationships
Negative float No negative float, re-check use of constraints
High duration Most activity’s duration shall be less than reporting period
Link to WBS element All activities shall be linked to activity, not WBS element (not allowed in P6)
DCMA 14 point assessment can be used for quantitative assessment guideline and basis

22. 22
Assessing Critical Activities Reliability
Check longest path continuity
Ideally, the activities in longest or critical path should be linked in FS sequences without any lag and
constraints, so it will be easier to monitor the changes when schedule updated
Some factors that may cause not continuous/ broken,
1. Use of constraint
2. Use of lag
3. Relationship from other project
4. Different calendar between activities

23. 23
Assessing Critical Activities Reliability
Check longest path continuity – 1. Use of Constraint
It seems not logical when the schedule has no critical activities in the first 3 days
Recommendation:
Remove any constraint that can make longest path broken, even the use of constraints shall be as
few possible in project schedule

24. 24
Assessing Critical Activities Reliability
Check longest path continuity – 2. Use of Lag
Use of lag may cause difficulty in analyzing the longest path and sometimes open ended activities
Recommendation:
Convert lag to activity, even the use of lag should be avoided in project schedule
open end

25. 25
Assessing Critical Activities Reliability
Check longest path continuity – 3. Relationship from other project
When you link the activities between multiple projects, longest path may be broken due to it
Recommendation:
All linked projects shall be opened simultaneously while calculating the float, and choose option to
calculate float based on finish date of “Opened project” instead of “Each project” in schedule option

26. 26
Assessing Critical Activities Reliability
Check longest path continuity – 4. Different calendar between activities
Non work period may be considered as floats when activities with different calendar are linked
Non work period (5 d/week)
Recommendation:
Check carefully the sequence between activities with different calendars, adjust the duration if
needed to make it unbroken

27. 27
Assessing Critical Activities Reliability
Check critical path integrity
If the number of delays in the longest path and project completion is not the same, then critical path
integrity is doubtful
Project duration is extended by 2 days due to change of longest path duration by 2 days, it means
longest path has good integrity
A2 duration changes from 3d to 5d
Recommendation:
Reassess schedule health and longest path continuity when the integrity check is failed

28. 28
Managing Critical - Near Critical Activities
05

29. 29
Managing Critical - Near Critical Activities
Managing critical - near critical activities properly can help project team to
prioritize the works and allocate the resources effectively
Gather actual work
information
Update project
schedule
Assess critical-near
critical activities
Develop critical
variance analysis
Verify and plan the
mitigation plan
Collect all actual work
information during
reporting period for
schedule updating
Update the project
schedule reflecting
actual work achievement
Assess the reliability of
critical and near critical
activities from
scheduling view
Record any update of
critical activities and
analyze its impact to
project completion/ key
milestones
Verify critical activities to
project teams and
develop mitigation plan
to maintain the schedule
or to get the schedule
back on track
Monitor progress performance and
mitigation plan execution
Critical activities management process in each period

30. 30
Managing Critical - Near Critical Activities
Mitigation plan shall be planned when activities exceed the schedule threshold
that was set and agreed in planning stage
Total float after
schedule update
Condition Mitigation Plan/ Action
> 10% PD - No need
≤ 10% PD - Close monitor
< 5% PD Potential to become critical Plan preventive actions to maintain/ shorten the remaining
duration to not becoming critical
< 0 day Delays still can be mitigated without
interrupting other divisions schedule
Plan short term corrective action (e.g., 1~3 month look ahead)
with more detailed target items to reduce delay impact
< 0 day Delays still can be mitigated but
interrupting other divisions schedule
Plan short-long term corrective action with more detailed target
items to reduce delay impact
< 10% PD Delay mitigation need to change
almost overall work sequences
Plan recovery plan that may include change of execution plan to
keep planned completion date (re-baselining may be needed)
PD: Project Duration
Sample of Schedule Threshold Narrative

31. 31
Managing Critical - Near Critical Activities
Sample schedule case: Project shall be completed on or before 9 Oct 18
Sample Schedule – Original

32. 32
Managing Critical - Near Critical Activities
Schedule update period 1: finish date shifts to 15 Oct 18 (6 days delay), resulting
negative total float by -6d
Sample Schedule – Update Period 1
 Not-started activity remaining duration shall be maintained as same as baseline duration unless there is
mitigation plan to shorten it
6 days delay

33. 33
Managing Critical - Near Critical Activities
Schedule is then grouped by float path (using free float) to monitor the critical
sequences and prepare mitigation plan
Sample Schedule – Update Period 1 – Group by Float Path
6 days delay
Activities are completed, so it is not considered as critical

34. 34
Managing Critical - Near Critical Activities
Mitigation plan is simulated to current schedule to clearly see its effort and result
Sample Schedule – Update Period 1 – Group by Float Path – Simulation of Mitigation Plan
3 days acceleration
5 days acceleration
 Step-1 is mitigation plan that will be done in the next period
 Step-2 is next mitigation plan after step-1 mitigation plan succeeded, this will be adjusted based on the
result of step-1 mitigation plan
3 days acceleration
Step-1 Step-2

35. 35
Managing Critical - Near Critical Activities
Mitigation plan step-2 is excluded from current schedule update report since it will
not be executed in current stage but still considered as next mitigation plan
Sample Schedule – Update Period 1 – Group by Float Path – Simulation of Mitigation Plan w/o Step-2
 Activities duration in mitigation plan step-2 shall be maintained as original since no corrective action is
taken in current stage
Step-1 Step-2
3 days acceleration
5 days acceleration

36. 36
Managing Critical - Near Critical Activities
Detailed mitigation plan is described in critical variance analysis
Sample Schedule – Update Period 1 – Critical Variance and Mitigation Plan
Description Div. Float
Path
Total Float Current Target Cause Corrective Action
Current Target Start Finish Start Finish
STEP-1
Design Basis Design 1 -6d -3d 03-Sep-18
Actual
15-Sep-18 - 15-Sep-18 Late final study result Consolidation to close all issues: 14-
Sep-18
Detail Design A Design 1 -6d -3d 16-Sep-18 30-Sep-18 16-Sep-18 27-Sep-18 Late design basis issuance Consolidation w/ client to speed up
review: 24-Sep-18
Design B Design 2 -4d 1d 16-Sep-18 25-Sep-18 16-Sep-18 20-Sep-18 Late design basis issuance Issue clean document: 19-Sep-18
Install B Cons. 2 -4d 1d 26-Sep-18 13-Oct-18 21-Sep-18 08-Oct-18 Late design B finalization due to late
design basis issuance
Start soon after Design B
Install C Cons. 3 3d 3d 14-Sep-18 06-Oct-18 14-Sep-18 06-Oct-18 Late design C receiving Start soon
STEP-2 (future mitigation)
Install A Cons. 1 -6d -3d 01-Oct-18 15-Oct-18 28-Sep-18 12-Oct-18 Late detail design A finalization due to
late design basis issuance
Construction steps will be studied in
detail to shorten duration at least by 3
days
Current schedule before mitigation
Expected schedule after succeeding mitigation plan

37. 37
Managing Critical - Near Critical Activities
Schedule update period 2: finish date is now 10 Oct 18 (4 days delay)
Sample Schedule – Update Period 2

38. 38
Managing Critical - Near Critical Activities
Mitigation plan execution in previous period shall be reviewed in order to prepare
advanced mitigation plan (step-2)
Sample Schedule – Update Period 2 – Review Previous Period Critical Variance and Target
Description Div. Float
Path
Total Float Target Actual/ Forecast Status Remark
Target Actual Start Finish Start Finish
STEP-1
Design Basis Design 1 0d - 15-Sep-18 - 15-Sep-18
Actual
Achieved
Detail Design A Design 1 0d -4d 16-Sep-18 27-Sep-18 16-Sep-18
Actual
28-Sep-18
Forecast
Not Achieved
Design B Design 2 1d 1d 16-Sep-18 20-Sep-18 16-Sep-18
Actual
20-Sep-18
Actual
Achieved
Install B Cons. 2 1d 1d 21-Sep-18 08-Oct-18 21-Sep-18
Actual
06-Oct-18
Forecast
Achieved
Install C Cons. 3 3d 3d 14-Sep-18 06-Oct-18 14-Sep-18
Actual
05-Oct-18
Forecast
Achieved
STEP-2 (future mitigation)
Install A Cons. 1 0d -4d 28-Sep-18 09-Oct-18 29-Sep-18
Forecast
10-Oct-18
Forecast
Not Achieved Advanced mitigation plan shall be prepared
Red : target was not achieved
Green : target achieved

39. 39
Managing Critical - Near Critical Activities
Schedule is grouped by float path
Sample Schedule – Update Period 2 – Group by Float Path

40. 40
Managing Critical - Near Critical Activities
Mitigation plan simulation for period 2
Sample Schedule – Update Period 2 – Group by Float Path – Simulation of Mitigation Plan
4 days acceleration
 Install A need to be shortened by 4 days instead of 3 days as previously planned since predecessor is late
from target

41. 41
Managing Critical - Near Critical Activities
Install A activity is detailed to monitor critical activities closer
Sample Schedule – Update Period 2 – Group by Float Path – Simulation of Mitigation Plan Detailed
Broken into 3 tasks
 If project scheduling rules do not allow new activities to be added to maintain baseline, then more detailed
schedule can be developed in separate schedule

42. 42
Managing Critical - Near Critical Activities
Detailed mitigation plan for next period
Sample Schedule – Update Period 2 – Critical Variance and Mitigation Plan
Description Div. Float
Path
Total Float Current Target Cause Corrective Action
Current Target Start Finish Start Finish
Detail Design A Design 1 -4d 0d 16-Sep-18
Actual
28-Sep-18 - 28-Sep-18 Late comment closing Accelerate final issuance
Install A Cons. 1 -4d 0d 29-Sep-18 13-Oct-18 29-Sep-18 09-Oct-18 Late detail design A finalization Increase work resources and work in 2
shifts
Detailed work steps are indicated in
schedule
Install B Cons. 2 3d 3d 21-Sep-18
Actual
06-Oct-18 - 06-Oct-18 Keep monitor
Install C Cons/ 3 4d 4d 14-Sep-18
Actual
05-Oct-18 - 05-Oct-18 Keep monitor

43. 43
Managing Critical - Near Critical Activities
Sample update period 3: Project is completed on time!
Sample Schedule – Update Period 3/ As-Built

44. Linkedin.com/in/indrapandu
WRAP UP!
1
Critical – near critical activities in project shall be clearly defined including its threshold in order to
prepare enhanced mitigation plan
Define Critical – Near Critical Activities
2
Reliable critical activity comes from reliable project schedule, therefore schedule shall be assessed
in order to have healthy project schedule
Assess Critical Activities Reliability
3
Mitigation plan for critical – near critical activities shall be planned and monitored to maintain
project completion date on schedule
Manage Critical – Near Critical Activities