Modeling Tough Scheduling Problems with Software

Alex S. Brownhttp://www.alexsbrown.com

Mitsui Sumitomo Marine Management (USA), Inc.

Objectives• Get Past Frustration (Intermediate)

• Learn New Tools and Techniques (Expert)

• Not For Beginners– Basic Skills Assumed– Assume Experience Using Scheduling Software

• Software-Brand Neutral - Not Taking Sides

• Interactive, Case-Study Format

Key Terms• Network Diagram

• Gantt Chart

• Two Types of Projects

Serial Dependencies Parallel Opportunities

Scenario• Six Tasks

• Three Resources

Four Directions - Pick One!• Resource Leveling

• Representing Hard & Soft Dependencies

• Quickly-Changing Work & Assignments

• Maintaining Schedules During Execution

Go!

Go!

Go!

Go!

Resource Leveling - Key Data• Gather Complete Data At the Start

– Resource start dates and availability– Vacations– Accurate work and duration estimates– Accurate sequence relationships

• Good Data is Essential• When Data Is Good Enough, Level To

Discover The Real End Date

Principles of Leveling• Find a Repeatable Method -- Level

Regularly

• Changes in Any Estimate or Assumption May Require Re-Leveling

• Leveling is Iterative -- Methods Should Allow Small, Frequent Adjustments

Scheduling Tools for Leveling• View Resource Use Over Time

• Adjust Key Task Info– Start Dates– Delays on Tasks– Allocation of Work Over Time by Task

• Resource Availability vs. Work Assigned

Resource/Task Total Work Week 1 Week 2Resource A 40 20 20 Construct #1 20 15 5 Construct #2 20 5 15

Breakout Discussion• Level the Scenario for 40-Hour Weeks, 8-

Hour Days for Each Resource• Different Approaches on the Handouts• Key Questions

– What method do you normally use?– Which is easiest to set up?– Which is easiest to maintain?

• Five Minutes for Discussion

Possible Solutions• Stretch All Work to Five Days Duration

• Make Work Sequential– Move Start Dates– Add Delays

• Break Down the Task List Differently to Simplify Leveling

Selecting A Technique• What is Easiest in Your Software?

• How Hard is Maintenance?

• What Methods Allow for Automation for All or Part of the Work?

• What is the Impact on Reporting and Analysis Techniques?– Critical Path– Earned Value

Questions & Answers on Leveling

Pick NextTopic

Hard & Soft Dependencies• Hard Dependencies MUST Be Obeyed

• Soft Dependencies SHOULD Be Obeyed

• Real-Life Schedules Often Break or Change Soft Dependencies to Achieve Required End Dates

• Challenge Your Assumptions:– Is It Really IMPOSSIBLE for Task B to Start

Until Task A Ends?

Issues with Dependencies• Software Usually Recognizes Only Hard

Dependencies

• Critical Path Analysis is 100% Dependent Upon an Accurate Network Diagram

• Documenting Dependencies is a Challenge

• Documenting Dependencies is Essential

Breakout Discussion• Scenario Uses Soft Dependencies• Soft Dependencies Driven By Resource

Limitations• Questions

– Where do you document dependencies?– What is the critical path?– What do you WANT the critical path to be?– How does the schedule respond to change?

Documenting Dependencies• Many Options

– Two Network Diagrams - “Hard Only” and Current

– Narrative Explanation of Dependencies– Separate Columns or Spreadsheets Track Hard

and Soft Dependencies

• Pick a Method You Can Maintain Easily

Dependencies in Software• Scheduling Software Usually Enforces

Dependencies Strictly (All Hard)

• Options– Only Enter Hard Dependencies - Satisfy Soft

Dependencies During Leveling– Enter Both Hard and Soft Dependencies for

Each Task, Update As Needed– Enter Only the Constraining Dependency

Consequences of Approaches• Calculation of Critical Path

• Clarity of Network Diagram– “Only Hard” is Clearest Diagram– “Hard & Soft” Creates Overlapping Lines– “Only Constraining” Looks Like a Serial

Project’s Network

• Respond to Change Differently -- Task Estimates vs. Task Assignments

Questions & Answers on Dependencies

Pick NextTopic

Quickly-Changing Schedules• Real Schedules Change Every Reporting

Period– Estimate Changes - Work & Duration– Assignment Changes– Resources Added, Removed, and Rescheduled– Resource Availability Changes

• Optimize Schedule, Make New Forecasts• The Only Certainty is Change Itself

Planning for Changes in the Plan• Predict Future Changes

– What is likely to change?– What changed often in the past?– What project risks will cause change?

• Create a Small Schedule with Typical Tasks• Try Making Typical Changes• Experiment, Experiment, Experiment to Find

Best Scheduling Techniques

Breakout Discussion• Start with Initial Scenario

• Apply Changes– Resources No Longer Available– Resources Available More Hours Per Week– Estimate Changes

• Model the Schedule Differently and Repeat– Hard and Soft Dependencies– Different Leveling Techniques

Change is Fundamental• Experiment with Change in a Small

Schedule– Best way to evaluate and compare different

techniques– Great way to explore, understand, and evaluate

scheduling software

• Best Techniques Will Vary -- Find the Best for Your Schedules, for Your Software

Change Drives Automation• Change is Difficult with Hand-Drawn

Schedules and Budgets• Software Facilitates Change by Updating

Every View of a Schedule Simultaneously• WARNING: If the Model is Poor, Software

Can Be MORE Difficult to Update• LESSON: Understand Basic Principles

BEFORE Automating

Questions & Answers on Quickly-Changing Schedules

Pick NextTopic

Maintenance During Execution• Key Steps

– Apply actual work– Update estimates for remaining work– Optimize the schedule and update forecasts

• Many Managers Shelve Schedules After Developing Them

• Schedule Maintenance Key to Learning as an Organization and as a Manager

Benefits of Maintenance• Compare Actuals to Estimates

– Improve estimates for next time– Improve control of work and scope

• Required for Earned Value and Benchmarking

• Accurate, Up-to-Date Forecasts of Delivery Dates

• Prove Scheduling Techniques

Package-Specific Features• Timesheets Automate and Distribute Entry

of Actuals

• Entry of Actuals Vary by Software Package

• Different Packages Reschedule Remaining Work Differently

• Do Not Focus on Software Differences, Focus on Creating a New Forecast

Breakout Discussion• Review Actual Progress After Week 1

• Schedule the Remaining Work

• Questions– Can you predict how your software would

reschedule the remaining work?– Do we change dependencies now that work is

started?

What SHOULD Software Do?• Actuals Sometimes Break “Rules” in the

Schedule– Actual work starts before predecessor is

complete– “Must Meet” deadlines missed

• Software Packages Make Assumptions and Raise Warnings -- Each Has a Different Approach

Responsibility As Software Users• Understand That Actual Work Might Break

Our Model

• Software May React Unpredictably When Our Models Are Wrong

• Understand Software Settings, Defaults, and Options

• Experiment, Experiment, Experiment -- Create Small Schedules to Test and Learn

Important Choices• Techniques Used When Building Schedule

Determine Maintenance Procedures

• Schedule Time to Update the Schedule

• Update the Schedule and Forecast New End Dates Regularly

• Larger Projects = Maintenance is Critical

• Larger Projects = Maintenance is Difficult

Questions & Answers on Schedule Maintenance

Pick NextTopic

Review - Four Tough Problems• Resource Leveling

• Representing Hard & Soft Dependencies

• Quickly-Changing Work & Assignments

• Maintaining Schedules During Execution

In the Paper• Exercises

• More Details on All Four Topics

• Comparison of Novice vs. Expert Use of Scheduling Software

• Ideas to Improve Your Skills

• References and Additional Reading

Complete Your Learning Experience

• This Presentation is a First Step

• Download the Paper

• Run Exercises Using Your Software

• Select Scenarios From Your Schedules and Try New Techniques

• Hear It and You Will Forget It

• Do It and You Will Remember It!

Questions & Answers• Contact Speaker at

http://www.alexsbrown.com or alexbrown@msigusa.com

• Evaluation Forms

• Feedback on New Case Study Format Appreciated

Modeling Tough Scheduling Problems with Software

Alex S. Brownhttp://www.alexsbrown.com

Mitsui Sumitomo Marine Management (USA), Inc.