Lecture 3.5: Work Dependencies,
Scheduling, IMP & IMS (SEF A16A)
Dr. John MacCarthy
UMBC CMSC 615
Fall, 2006
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Agenda
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Types of Schedules
Event-Driven Schedules
Events and Entry/Exit Criteria
Resource Loaded Schedules
Integrated Management Plan (IMP)
Example PERT Chart
“Time-Expressed” Schedules
Integrated Management Schedule (IMS)
Example Gantt Chart
Scheduling Tools
Summary
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Types of Schedules
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Event-Based Schedule:
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Generally referred to as the Integrated Management Plan (IMP)
Generally implemented as a Program Evaluation and Review Technique (PERT) Chart
Identifies key engineering management events and relates them to the WBS
Identifies the key tasks and results expected to permit key events
Identifies key dependencies between tasks and events
Serves as basis for:
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Schedule Control
Resource (& Cost) Control & Prioritization
Planning & Measuring Cost/Schedule Progress, i.e. Earned Value
A valid time-based (detailed) schedule
“Time-Expressed” Schedule:
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Generally referred to as the Integrated Master Schedule (IMS)
Generally implemented as a Gantt Chart
Provides dates
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For key events
By which tasks are to be started and ended
Shows key temporal dependencies between tasks and events
Resource loaded time-based schedules serve as basis for Earned Value Measurement
Generally derived from the Event-based Schedule (PERT Chart)
Note that my (and industry) usage of the term IMS is inconsistent with the SEF use of term
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Event-Driven Schedules
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DoDI 5000.2 indicates schedules should be
“EVENT-DRIVEN,” not “Time-Driven”:
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Identify key events required to achieve
programmatic success
Identify entry/exit criteria for those events
Identify tasks that must be performed to
satisfy entry/exit criteria
Identify dependencies between tasks and
events
Identify time to accomplish required tasks
(to satisfy entry/exit criteria)
(Time) Schedule the events (and tasks)
accordingly
Key SE Events:
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Do not let a date on a schedule force an
event,
The successful completion of event entry/
exit criteria should drive when an event
occurs
The Integrated Management Schedule
(IMS) is DoD “Event-Driven” Schedule
(generally represented as a PERT Chart)
Process:
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SRR
SFR
PDR/SSR
CDR/TRR
SVR/FCA
PCA
Key Events generally have documented Entry
and Exit Criteria
Reality Check - All programs have real
end dates associated with them. If the
time-schedule derived from the eventschedule does not meet the
required end date:
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Entry/exit criteria may need adjustment
Task & task estimates may need
adjustment
Customer may need to revise end-date
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Example Event Exit Criteria
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Events have associated (Entry and) Exit Criteria
Events should not occur until (Entry and) Exit Criteria can be met
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“Event-Based Schedule” Development
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Identify what artifacts/
products (& associated
tasks) need to be
complete for each WBS
element for each Event
Identify artifact/ product/
tasks dependencies
Provides basis for Earned
Value
Graphic provides one
example of how this can
be done
Each program will have its
own process and forms
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Example PERT Chart
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A PERT Chart is essentially a flow chart showing the dependencies between
events and activities (what activities need to be completed prior to what events
and the complete/start dependencies between activities)
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Integrated Management Plan (IMP)
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The IMP is.
The IMP is generally used to develop a
schedule by fixing Customer dictated Event
dates and determining the time required to
complete required activities.
Generally the IMP takes the form of a
(PERT) Chart
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Resource Loading of Schedules
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Generally one identifies the following data for each task (to develop artifacts and
support events):
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Event(s) Supported
WBS Reference (WBS Element and Work Package)
Start Date
End Date
EV milestones and credit
Task Dependencies (input/output)
Resources required (generally staff months and skill type)
As such, the data exists to “resource load” the schedule
As one transitions from an “event-based” schedule to a “time-based” schedule, one can
determine the (time-phased) staffing profile for the program, i.e., how many
people (full time equivalents (FTEs)) are required (with what skills) as a function of
time
Note: For a given amount of work, as the schedule is compressed, the number of FTEs required (for
each skill set) will increase.
Note: Schedule compression and elongation each result in (different) inefficiencies that drive up the
resource count
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“Time-Expressed” Schedules
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In order to manage a program, one must
eventually assign dates to Events and Tasks
The result is a “Time Expressed” or
“Calendar-Based” Schedule
This is usually represented by a Gantt Chart
Time-Expressed Schedules are generated
from the IMS
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Integrated Master Schedule (IMS)
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Technically the IMS is a
database that includes:
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All Milestones/ Events
All Activities/Tasks & Activity/Task
start/stop dates
All Activity/Task & Event
dependencies
WBS/Work Package References
Often associated WBS/Work
Package information such as staff
loading and cost
The IMS is almost never seen in its
entirety, rather different “Views” of
the IMS are provided depending on
the purpose
The views are generally provides as
“Gantt Charts”
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Levels/Views of the IMS:
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Top-Level:
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Total Detailed (the “Real”) IMS:
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All Milestones/Events, Activities, & Dependencies
Provides basis for other views
Rarely seen by anyone
IPT Mid-Level:
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Major Milestones/Events, Activities, & Dependencies
Used by Top Management and the Customer
Shown at Technical Reviews and PMRs
Major Milestones/Events, Activities, & Dependencies of
interest to an IPT
Used by IPT Manager
Shared with IPT and Management
Work Package Detailed:
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All Milestones/Events, Activities, & Dependencies
associated with a given work package
Developed & Used by Work Package Lead
Shared with Mid-level management
Serves as building block for Total Detailed (“Real”) IMS
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Gantt Chart Example
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A Gantt Chart represents:
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Events as “Taco Chips”
Activities as “bars”
Dependencies as “arrows”
Each Event and Activity is
labeled as a Row
Events & Activities may be
Decomposed/Nested
The date of an Event and
the duration each activity is
indicated by its location in
the Row
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Scheduling Tools
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Generally the IMP and IMS will be developed in a single tool that:
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Permits one to develop a Event-Driven IMP “Schedule” (as a PERT Chart)
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Events & Activities
Dependencies
Include WBS/Work Package References
Enter planned and actual Resource Loading data
Enter planned and actual cost data
Enter planned and actual start/stop dates for events & activities
Permits one to generate the Time-Expressed IMS & IMS Views (as Gantt Charts)
Permits one to generate planned and actual Resource Profiles
Permits one to generate an Earned Value Report
Examples:
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MS Project
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Summary
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Schedules should be “Event-Based”
Events should not occur until all Entry and Exit Criteria are fulfilled
The IMP is an Event-Based Schedule that is often represented as a
PERT Chart
Events and activities in an IMP should be tied to the WBS
Schedules need to be “Time-Expressed”
The IMS is a database that includes Time-Expression
The Gantt Chart provides a IMS may be viewed in a Time-Expression
Schedules are generally Resource Loaded
Tools exist for the development of IMPs and IMSs that may also be
used to generate Earned Value Reports and Resource Profiles
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