Tools For Innovation: The Design Structure Matrix

Tools For Innovation:The Design Structure MatrixThomas A. Roemerand Steven EppingerSummer 02, 15-761MITSloan

Outline Overview Design Structure Matrix (DSM) Basics How to createClassificationThe Iteration Problem: Traditional Project Management Tools and ProductDevelopmentIncreasing Development SpeedSequencing, Partitioning and SimulationThe Integration Problem: DSM ClusteringOrganizational Structures & Product ArchitecturesMITSloan

Classical Project ManagementToolsGantt Charts Graph-based: PERT, CPM, IDEFActivity TimeMITSloan

Characteristics Complex DepictionFocus on Work Flows Ignore Iterations & Rework DSM focuses on Information FlowsTest results, Planned design reviews, Designmistakes, Coupled nature of the processDecomposition & Integration Assume optimal Decomposition & StructureIntegration of Tasks not addressedMITSloan

Design Iteration Iteration: The repetition of tasks due to newinformation. Fundamental in Product development Changes in input information (upstream)Update of shared assumptions (concurrent)Discovery of errors (downstream)Often times hiddenUnderstanding Iterations requires Visibility of information flowsMITSloan

Decomposition andIntegration Decomposition:Dividing a complex probleminto smaller sub-problems.Integration:Combining sub-problems toachieve set goals.MITSloan

A Graph and its TSloan

Creating a DSM Design manualsProcess sheetsStructured expert interviews Interview engineers and managersDetermine list of tasks or parametersAsk about inputs, outputs, strengths ofinteraction, etcEnter marks in matrixCheck with engineers and managersQuestionnairesMITSloan

Four Types of DSMsIterationActivity based DSMParameter based DSMSequencingPartitioningSimulationIntegrationTeam based DSMProduct Architecture DSMClusteringMITSloan

Iteration Focused ToolsConcepts, Examples, SolutionApproachesMITSloan

Sequencing Tasks in ProjectsPossible Relationships between led)BDependent(Series)MITSloan

Sequencing Algorithm Step 1: Schedule tasks with empty rows firstStep 2: Delete the row and column for that taskStep 3: Repeat (Go to step 1)Step 4: Schedule tasks with empty columns lastStep 5: Delete the row and column for that taskStep 6: Repeat (Go to step 4)Step 7: All the tasks that are left unscheduled arecoupled. Group them into blocks around the diagonalMITSloan

Task Sequencing ExampleFigure 4 spcrft/kristof/SPfinal.htmlSpace Shuttle Main EngineMITSloan

Product DecompositionEngine ComponentsMITSloan

Turbo PumpMITSloan

Project ScopeActivityActivityQuestionnaireMSMMWWOrganized Activity DiagramMSWVerifyVerifyA-A & A-IA-A & A-IMatricesMatricesInformationActivityActivityGate ReviewsII II Key FunctionsKey FunctionsandandClientsClientsStage Overlapping.ConsultConsultKey FunctionsKey FunctionsandandExecutivesExecutivesFinal ProcessStructureTime Cost alysisOpportunityOpportunityCostsCostsMITSloan

Corresponding opean J. of Operational r.Res.Res.19991999 lopment r.Oper.Res.Res. elopmentDevelopmentRoemer&Ahmadi,InRoemer & Ahmadi, InreviewreviewatatOper.Oper.Res.Res.MITSloan

Finding Coupled StagesBlockCreationBlock DecompositionDesign TimeComputationMITSloan

Dependency Relations inConceptual Design BlockFor this graph, seeTime-Cost Trade-Offs in Overlapped ProductDevelopment Processes by Roemer, Ahmadi &Wang, Operations Research, 2000.MITSloan

Block Decompositionmin aij nij yijij AM xs.t.m 1im 1, iN xim C , mi 1xim M xh m 1jh yij 0, i, j , mxim , yij {0,1}, i, j , mi,j index for activities, i,j 1,2, ,N;m index for stages, m 1,2, ,M;A the set of directed arcs in the design graph;aij the level of dependency of activity i on j 1 if activity i is assigned to stage mxim 0 otherwise 0 if arc ij is a feed back between stagesyij 1 otherwise Wnij 1(a large number) if aij 1otherwiseMITSloan

Resulting Structure forConceptual Design BlockFor this graph, seeTime-Cost Trade-Offs in Overlapped ProductDevelopment Processes by Roemer, Ahmadi &Wang, Operations Research, 2000.MITSloan

Lead Time EstimationExp. Iterationsµ ji (I P ) 1Markov ChainActivity DurationTi ti e 1 / β i [t (tµ1i 1n 10iiStage DurationT i 1 Tik) t e0i λi n.3].5111.223.5.5STMITSloan

Decomposition and DurationBlock n Degree (Number of Process Stages)MITSloan

Duration Increase1000%3530Number of 67891011Number of IterationsStage Size and Duration0Number of ActivitiesMITSloan

XTask ADSM Simulation Task CXXTask A requires input from task CPerform A by assuming a value for C’s outputDeliver A’s output to BDeliver B’s output to CFeed C’s output back to A Task BCheck initial assumption (made by A)Update assumption and repeat task A.MITSloan

Simulating ReworkRTask ATask BTask CXXR is the probability that Task A will be repeatedonce task C has finished its work.R 0.0 : There is 0 chance that A will berepeated based on results of task C.R 1.0 : There is 100% probability that A willbe repeated based on results of task C.MITSloan

Simulating 2nd Order ReworkXTask ATask BTask CR2XSecond Order rework is the rework associated with forwardinformation flows that is triggered by feedback marks.First order rework: Output of task C causes task A to do some rework2nd order rework: Consequently there is a chance tasks depending onA (e.g. task B) will also be repeated.MITSloan

Simulating Rework ImpactITask ATask BTask CXXI 0.0 : If task A is reworked due to task C results,then 0% of task A’s initial duration will be repeatedI 1.0 : If task A is reworked due to task C results,then 100% of task A’s initial duration will berepeatedMITSloan

Simulation Results DSM contains reworkprobabilities andimpactsCost and time add upMany runs produce adistribution of total timeand costDifferent tasksequences can be triedRelated reading: “Modeling and Analyzing Complex System Development Cost, Schedule, and Performance” Tyson R.Browning PhD Thesis, MIT A&A Dept., Dec 99MITSloan

Gantt Chart with Iteration Typical Gantt chart shows monotone progressActual project behavior includes tasks stopping, restarting,repeating and impacting other tasksRelated Reading: “Modeling and Analyzing Complex System Development Cost, Schedule,and Performance” Tyson R. Browning PhD Thesis, MIT A&A Dept., Dec 99MITSloan

Lessons Learned: Iteration Development is inherently iterative.Understanding of coupling is essential.Iterations improve quality but consumes timeIteration can be accelerated through: Information technology (faster iterations)Coordination techniques (faster iterations)Decreased coupling (fewer iterations)Two Types of Iteration: Planned Iterations (getting it right the first time)Unplanned iterations (fixing it when it’s not right)MITSloan

Integration Focused ToolsConcepts, Examples, SolutionApproachesMITSloan

Team Selection Team assignment is often opportunistic “We just grab whoever is available.”Not easy to tell who should be on a teamTradition groups people by functionInfo flow suggests different groupingsInfo gathered by asking people to recordtheir interaction frequency with othersMITSloan

Clustering a DSMA B C D E F GA ABBCCDDEEFFGGNo DependencyLowA F E D B C GA AFFEEDDBBCCGGHiMITSloan

Alternative ArrangementOverlapped TeamsA F E D B C GA AFFEEDDBBCCGGNo DependencyLowA F E D B C GA AFFEEDDBBCCGGHiMITSloan

GM’s Powertrain Division 22 Development Teams into four SystemTeams Short block: block, crankshaft, pistons, conn. rods,flywheel, lubricationValve train: cylinder head, camshaft and valvemechanism, water pump and coolingInduction: intake manifold, accessory drive, aircleaner, throttle body, fuel systemEmissions & electrical: Exhaust, EGR, EVAP,electrical system, electronics, ignitionMITSloan

Lessons Learned: Integration Large development efforts require multipleactivities to be performed in parallel.The many subsystems must be integrated toachieve an overall system solution.Mapping the information dependence revealsan underlying structure for systemengineering.Organizations and architectures can bedesigned based upon this structure.MITSloan

Conclusions The DSM supports a major need in productdevelopment: documenting information that is exchangedIt provides visually powerful means fordesigning, upgrading, and communicatingproduct development activitiesIt has been used in industry successfullyMITSloan

DSM Web Page http://web.mit.edu/dsm/It contains A tutorial Links to other DSM sites Over 100 references of DSM literature Analysis toolsMITSloan

Suggested Reading“Innovation at the Speed Of Information”By Steven D. EppingerHBR January 2001MITSloan

Gantt Chart with Iteration Typical Gantt chart shows monotone progress Actual project behavior includes tasks stopping, restarting, repeating and impacting other tasks Related Reading: “Modeling and Analyzing Complex System Development Cost, Schedule, and Performance” Tyson R. Browning PhD Thesis, MIT A&A Dept., Dec 99