Work Breakdown Structures

Transcription

1 Wrk Breakdwn Structures The WBS 1 is a hierarchal decmpsitin f the ttal scpe f wrk t be carried ut by the prject team t accmplish the prject bjectives and create the required deliverables 2. The WBS shuld be structured in accrdance with the way wrk will be perfrmed and reflect the way in which prject s cst and schedule data will be summarised and reprted. The WBS is ne f many different types f breakdwn structure used in prject management 3. The mst cmmn structure fr a WBS is a 4 t 6 level indented structure, where the first three are managerial levels describing (fr example) the ttal prject, the prject phases and the cntrl accunts. The lwer level(s) are technical levels culminating in the wrk packages. Where a cmpnent f wrk is t be utsurced t a separate cntractr, the prject s WBS stps at the cntrl accunt r wrk package level that describes the cntracted wrk. Lwer level detail shuld be incrprated in a WBS maintained by the cntractr. WBS Nmenclature: WBS element: Any single cmpnent in the WBS diagram the cmpnent can be at any level. Types f cmpnent include: Parent: A higher level element in the WBS that is decmpsed int tw r mre lwer level elements (children) Child: A lwer level element in the WBS that is rlled up int a single higher level element (parent). Parent/Child descriptins are relative; an element can be bth a parent f lwer level elements and the child f a higher level element. 1 The cncept f wrk breakdwn structure develped as part f the Prgram Evaluatin and Review Technique (PERT) by the United States Department f Defense (DD). While the term "wrk breakdwn structure" was nt used, PERT rganised the activities int prduct-riented categries. By June 1962, DD, NASA and the aerspace industry published PERT/COST System Design, which described the WBS apprach. This guide was endrsed by the Secretary f Defense fr adptin by all services. On the 1 st Nvember 1968, the DD issued "Wrk Breakdwn Structures fr Defense Materiel Items" (MIL-STD-881), a military standard requiring the use f wrk breakdwn structures acrss the DD. This standard has been revised several times, mst recently in PRINCE2 uses the cncept f Prduct Breakdwn Structure (PBS). Whilst the deliverables that make up the final prduct t be delivered t the client are always the majr part f any WBS, the PMI definitin ensures there is n pssibility f missing any f the wrk required t be accmplished by the prject team including prject management activities, safety functins, etc. Mdern PRINCE2 practice has been t extend the cncept f prduct t include all f the utputs frm a prject including internal reprts, etc. s in effectively there is very little difference between a WBS and a PBS. Hwever, fr the purpses f PMI examinatins assume the terms ttal scpe f wrk and deliverables encmpass mre than just the prduct ; r t put it anther way, the prduct is nly part f the ttal scpe f wrk. Fr mre n the difference between PBS and WBS see: 3 Fr mre n prject breakdwn structures see: First published 12 th June 2010 augmented and updated.

2 Wrk Package: the lwest level f any branch f the WBS. The wrk package is a defined sectin f prject wrk that prduces a deliverable (either a part f the prduct r smething required fr the management f the prject such as a risk management plan). The Wrk Package shuld be at a level f detail apprpriate fr the prject, small enugh t allw effective planning, management and cntrl f the wrk required t accmplish the scpe included in the package. The wrk package is nrmally the pint f integratin fr schedule, cst, quality, and risk infrmatin and shuld be at a level f detail that allws: Adequate cst and duratin estimates t be develped It is manageable thrugh the assignment f respnsibility and authrity - level f delegatin It is able t be integrated and measured - the whle package can be seen It is autnmus and unambiguus What is initially an adequate level f detail can change as the prject develps and mre infrmatin becmes available (prgressive elabratin). Planning Package: the lwest level f any branch f the WBS where that branch is expected t be decmpsed int greater detail at a later date; generally when either time allws, r mre infrmatin becmes available. The Planning Package cvers a defined scpe f wrk and acts as a temprary hlder f the estimated time, cst and ther factrs needed t accmplish the scpe. Until the Planning Package is brken dwn int smaller cmpnents, the scpe cvered by the Planning Package is represented in the schedule, cst and ther affected plans as a high level summary entry. Planning Packages must be brken dwn int wrk packages (r cnverted int a wrk package) and the schedule, cst and any ther affected plans updated befre wrk cmmences n that part f the scpe. Cntrl Accunt (r Cst Accunt): A management cntrl pint where the integratin f scpe, budget, actual cst, and schedule takes place, and where the measurement f perfrmance will ccur. Cntrl accunts (CA) are placed at selected pints (specific cmpnents at selected levels) f the WBS. Each CA may include ne r mre wrk packages, but each wrk package may be assciated with nly ne CA. Each CA is assciated with a specific rganisatinal cmpnent (persn) in the OBS 4. The respnsible manager is frequently designated as the Cst/Cntrl Accunt Manager r CAM. 4 OBS = Organisatinal Breakdwn Structure the staff reprting relatinships within the prject. The intersectin f WBS and OBS may be a cntrl accunt r a wrk package. It defines the pint f management respnsibility fr a deliverable r a series f deliverables. 2

3 WBS dictinary: The Wrk Breakdwn Structure Dictinary is a cmpanin dcument t the wrk breakdwn structure (WBS) that describes each WBS element. It can be in any practical frmat, but fr large prjects a database is nrmal. Fr each WBS element, the WBS Dictinary includes a statement f wrk and a list f assciated activities and milestnes. Other infrmatin may be included: respnsible rganizatin, start and end dates, resurces required, an estimate f cst, charge number, cntract infrmatin, quality requirements, and technical references t facilitate perfrmance f the wrk. It is imprtant that the WBS dictinary prvides cncise, relevant, and sufficient infrmatin in the same frmat fr every element. The WBS dictinary will generally include: The cde f accunts identifier (WBS number) The descriptin f the element, and exactly what will be dne (referencing the specificatin, etc) What is required t allw the wrk package t start Assciated activities, and milestnes (referenced t the schedule) Any assumptins, cnstraints, r identified risks Wh is respnsible fr perfrming the wrk (persn r rganisatin, may be internal r external) Wh is respnsible fr managing the wrk (must be a manager wrking fr the prject manager) What are the deliverables, and wh will receive the deliverables The estimated duratin, resurces and cst fr the wrk package Hw prgress will be measured WBS Levels: Establish the hierarchical structure f the wrk breakdwn structure. Typically the highest level f the WBS is identified as level 0. The level typically frms the first part f the WBS element number: 3

4 Guidelines fr develping a WBS: A well designed WBS has the fllwing characteristics: Clear directin/definitin: Make sure the prject initiatin has been fully cmpleted and the parameters f what s in and what s ut f scpe agreed befre develping the WBS. Cmpleteness: The WBS shuld describe all f the wrk needed t cmplete the whle prject. And there shuldn t be anything in the WBS that isn t part f the prject. The 100% Rule: The highest tw levels f the WBS shuld include 100% f the wrk f the prject and nly the wrk needed t cmplete the authrised scpe. When dcumenting lwer level elements (children) underneath a WBS element (parent), the children must cmpletely and exactly describe the same amunt f wrk as the parent (100%), just in mre detail. Apprpriate level f detail: Only develp the WBS t an apprpriate level f detail ne that prvides adequate infrmatin t plan, manage and cntrl the prject withut creating excessive data. The decmpsitin Rule: Each element f the WBS decmpses int at least tw children (if n further decmpsitin is needed (r pssible) d nt g t the next level fr this branch f the WBS). Each child has nly ne parent (a WBS element must nt be cnnected t 2 higher level elements). Change Cntrl: Prcesses need t be develped t manage, and retain an audit trail f, the fllwing changes: Between different branches f the WBS - (scpe and budget deleted must equal scpe and budget added, this includes transfers frm cntingency elements t wrk packages affected by a risk event) Between the WBS and management reserves held utside f the WBS (the WBS shuld include internal cntingencies available t the prject team and rules fr their use). Between the WBS and the external client where changes t scpe (additins r deletins) are authrised thrugh the prject change cntrl system. Links t the Schedule 5 : The activities in the prject schedule fllw the 100% rule. Each wrk package r planning package shuld decmpse int ne r mre schedule activities. Planning packages are typically represented by a single summary activity (eg, Allwance fr testing = 8 weeks); this summary activity will be replaced by mre detailed activities nce the full requirements f the wrk are defined 6. Nrmal wrk packages typically expand int a significant number f activities and milestnes that fully define the sequence and duratin f the wrk needed t cmplete the package. The activities shuld define 100% f the effrt needed t accmplish the wrk package. Each schedule activity shuld nly rll up int a single WBS element. Links t Earned Value Management 7 : Mst EV systems aggregate/integrate infrmatin at either the wrk package level r the cntrl accunt level. This level f granularity balances the effrt needed t identify and allcate actual cst data with the usefulness f the infrmatin prvided. In mst rganisatins accurately dividing and allcating actual csts t the schedule activity level is nearly impssible whereas rlling up schedule prgress data t a wrk package is straightfrward. 5 Fr mre n schedule management see: 6 See rlling wave planning : 7 Fr mre n Earned Value see: 4

5 The Earned Value methdlgy invlves mre then just calculating frmulae. Where a variance is identified, the respnsible manager is expected t assess the reasn and recmmend recvery actins. This requires a single pint f management respnsibility fr each wrk package and cntrl accunt. Mre infrmatin: Practice Standard fr Wrk Breakdwn Structures 2 nd Editin (available as a free PDF dwnlad fr members see next page) Other WBS Standards: ISO 21511:2018 Wrk breakdwn structures fr prject and prgramme management MIL-STD-881D (April 2018), Department f Defense Standard Practice, Wrk Breakdwn Structures fr Defense Material Items ASTM E Standard Classificatin fr Life-Cycle Envirnmental Wrk Elements Envirnmental Cst Element Structure ASTM E2103 / E2103M 13, Standard Classificatin fr Bridge Elements UNIFORMAT II ASTM E (2015) Standard Classificatin fr Building Elements and Related Sitewrk UNIFORMAT II Plus ther ASTM Standards Diagram abve PMI frm the WBS Practice Standard. 5

6 Fr a discussin n the ther types f prject breakdwn structures including CBS, RBS, BM and thers see: Dwnladed frm Msaic s PMKI Free Library. Fr mre papers fcused n Scpe Management see: Or visit ur PMKI hme page at: Creative Cmmns Attributin 3.0 Unprted License. Fr mre infrmatin n scheduling and planning, visit Msaic s planning and scheduling hme page at: 6