Inadequate or hapless range definition, which negatively correlates to the undertaking public presentation, has long been recognized as among the most jobs impacting a building undertaking[ 1 ]. Due to hapless range definition, concluding undertaking costs can be expected to be higher because of the inevitable alterations which interrupt undertaking beat, cause rework, increase undertaking clip, and lower the productiveness every bit good as the morale of the work force[ 2 ]. Unfortunately many proprietor and contractor organisations do a hapless occupation of adequately specifying a undertaking ‘s range taking to a hapless design footing[ 3 ]. Scope definition activities take topographic point at the pre-project planning stage.
“ Pre-project planning is the undertaking stage embracing all the undertakings between undertaking induction to detailed design. Development of the undertaking range definition bundle is a major subprocess in this stage ”[ 4 ]. The Construction Industry Institute ( CII ) defines preproject planning as the procedure of developing sufficient strategic information with which proprietors can turn to hazard and make up one’s mind to perpetrate resources to maximise the opportunity for a successful undertaking[ 5 ]. The range definition bundle when decently done, gives information to analyse and turn to undertaking hazard every bit good as signifier a footing for estimations and agendas which would enable direction take determination to perpetrate resources to the undertaking. “ Research has shown the importance of preproject planning on capital undertakings and its influence on undertaking success. Findingss of a Construction Industry Institute ( CII ) survey carried out in 1994 proved that higher degrees of preproject planning attempt consequences in important cost and agenda nest eggs.
Specifically, the research survey categorized 53 capital installation undertakings into three different strengths of preproject be aftering attempt and compared entire possible cost and agenda public presentation differences as follows:
A 20 % cost nest eggs with a high degree of preproject planning attempt
A 39 % agenda nest eggs with a high degree of preproject planning attempt
Because of the important nest eggs associated with improved undertaking predictability, the survey concluded that a complete range definition prior to project executing is imperative to project success ”[ 6 ].
The undertaking range defines what the work is ( i.e. , the work that must be performed to present a merchandise, service, or consequence with the specified characteristics and maps )[ 7 ]. Project range definition is the procedure by which undertakings are defined and prepared for executing and It is at this important phase where hazards associated with the undertaking are analyzed and the specific undertaking executing attack is defined[ 8 ].
It follows from above definitions that if the work to be done in a undertaking is non clear or non decently defined, the executing of such undertaking will run into jobs. One of such jobs is cost overproductions. “ Poor range definition and loss of control of the undertaking range rank as the most frequent lending factors to be overproductions ”[ 9 ].
A range is better understood when interrupt down into smaller manageable spots or constituents and the WBS helps to make this. The WBS is a tree construction of in turn farther dislocations of work range into constituent parts for planning, delegating duty, managing, commanding, and describing undertaking advancement[ 10 ]. The top of the tree represent the whole and subsequent degrees represent divisions of the whole on a degree by flat footing until the smallest component desired is defined[ 11 ]. What the WBS contains are scope deliverables and non the activities and undertaking to carry through the deliverables. These undertaking and activities are covered in the undertaking agenda. However a agenda draws from the lowest degree of the WBS which is the work bundle.
The WBS is farther defined as “ an effectual show technique for specifying and forming undertaking work. For the proprietor, the WBS represents what is being bought while for the contractor, it contains all work being performed on the undertaking ”[ 12 ]. The WBS is derived from the Asset Owner ‘s range statement.
The WBS does non stand entirely, as a lexicon of existent range must attach to the WBS construction[ 13 ]. The WBS dictionary describes the particulars and exact range of each deliverable.
While the WBS is an effort to decently specify range its success has nevertheless been limited. The chief ground is that its elements and descriptions are non standardized even within the same organisation. Some organisations and undertaking directors are even confused about the proper usage of the WBS. Humphreys, G, 2002, alluded to this confusion when he asked the inquiry, “ If this structured attack to forming the range of work ( mentioning to WBS ) is normally used, why is there confusion? ”[ 14 ]. Humphreys ‘ reply is that some individuals use the WBS to reflect the organisation that is carry throughing the work instead than the work itself[ 15 ]. Other misconceptions are comparing the WBS with a agenda or list of activities to present the plants. The terminal consequence of these misconceptions and deficiency of criterions is hapless range definition.
Poor range definition refers to scope whose definition is uncomplete, unequal, inaccurate or obscure. As before stated hapless range definition is the root cause of many undertaking failures. One may desire to inquire, what are the grounds for hapless range definition? I province below a few of the grounds:
Absence or non usage of a range definition tool
Absence of standardised WBS
The hastiness to acquire budget blessing
Poor interface between Engineering ( Design ) and undertaking squad
Customers/Client non doing up their heads on clip.
Incompetence of design squad
Misinterpretation of clients demands
For 1st clip plus proprietors ; non grasp of the terminal merchandise from the beginning.
Owner non willing to perpetrate resources for full range definition
The demand to better undertaking range definition arises from the impact hapless range definition has on undertakings. Where range definition is hapless a undertaking is impacted in several ways. Some of these impacts are summarized here below:
Impact on cost estimations: Poor scope definition leads to detain in the bringing of estimations, over or under appraisal, high degree of eventuality allowance and uninterrupted alteration of the estimations as omitted points are added or inaccurate points are corrected. Furthermore concluding cost will be higher than budgeted. Harmonizing to O’Connor and Vickroy 1986, concluding undertaking costs can be expected to be higher because of the inevitable alterations which interrupt undertaking beat, cause rework, increase undertaking clip, and lower the productiveness every bit good as the morale of the work force[ 16 ].
Impact on agenda: Poor scope definition leads to schedule slippage and accordingly late bringing of the undertaking. A typical illustration is the add-on of necessary work points that were omitted from the range the agenda was based on. These will necessitate extra clip to be after and put to death. There would besides be holds ensuing from the integrating of the new plants into the bing plants as the undertaking beat will be disrupted and some points reworked. Poor range definition leads to an unrealistic agenda and this will give false information during advancement measuring. This means that a contractor could be overpaid or underpaid when earned value measuring is based strictly on the agenda. Another impact is that resources will be wrongly allocated to activities as their exact range is unknown.
Impact on hazard appraisal: One of the hazard events that undertakings cater for is deficiency of, or hapless range definition. This hazard is mitigated by the usage of eventuality, pecuniary in instance of cost estimations and extra resources or longer continuances in footings of agenda. Contingency is an sum added to an estimation or agenda to let for alterations that experience shows will probably be required[ 17 ]. These are normally referred to as “ Known Unknowns ” . Experience has shown that one time a eventuality is provided, it is frequently used up. Furthermore the cost of the alterations covered by eventuality for points that are non similar to bing plants are higher because of clip difference and deficiency of competition during the executing stage, therefore the plus proprietor pays more than he should hold paid if the range was wholly defined before executing stage.
Claims and many alteration orders: Poor scope definition leads to schedule slippage which in bend leads to contractual claims for extension of clip every bit good as extended undertaking direction, caput office operating expense and site indirect cost. Apart from clip extension claims, there would besides be claims for loss of net income, underutilization of planned resources, standby clip necessitated by many range alterations and outstanding work range definitions and elucidations.
Where there is schedule slippage, the undertaking proprietor may order acceleration steps to unclutter out the slippage. The cost for this acceleration is recoverable by the contractor if the cause of agenda slippage is due to hapless range definition. The undertaking proprietor ends up paying more than he should hold paid if range was good defined.
Undertaking Abandonment: If the impacts discussed above are extended, the undertaking may be abandoned as the proprietor may non hold the necessary financess to go on with the plants. This is normally the instance with many authorities undertakings. Furthermore the return on investing ( ROI ) may no longer be attractive coercing the proprietor to abandon or suspend the undertaking.
If we must avoid or minimise the above impacts, a batch more work demand to be done at specifying the undertaking range. Following this demand for improved undertaking range definition, the Construction Industry Institute ( CII ) funded a research which resulted to the development of a undertaking definition tool, called the Project Definition Rating Index ( PDRI ) , Industrial version in 1996. The Building version followed in 1999.
The following section of this paper will discourse the Project Definition Rating Index and how it is used to better undertaking range definition
The Project Definition Rating Index ( PDRI ) is a undertaking direction tool designed to increase the likeliness of undertaking success by bettering undertaking range definition, specifically by placing lacks in range definition early during the front-end planning procedure[ 18 ]. Cho C. S and Edward Gibson Jr described it ( PDRI-Industrial ) as a range definition tool that is widely used by contrivers in the industrial undertakings sector[ 19 ]. Edward Gibson Jr ( 2004 ) described it as a hazard direction tool as it identifies and steps hazards related to project range definition[ 20 ].
There are two versions of this tool, the PDRI Industrial undertakings and PDRI Building undertakings. PDRI Industrial was developed in 1996 for Industrial undertakings such as refineries, chemical workss, power workss and heavy fabrication while the edifice version was developed from the Industrial version in 1999. It covers assorted constructing types such as offices, schools, flat edifices, hotels etc.
The construction of the PDRI is as follows:
Table 1: PDRI Structure[ 21 ]
Please see Appendix 1[ 22 ]for description of the subdivisions, classs and elements ( PDRI Buildings )
The elements are critical range definition elements divided into classs and subdivisions as shown in table 1 above. The elements are arranged in a leaden mark sheet format and supported by 38 ( 34 for PDRI Industrial ) pages of elaborate description and checklist[ 23 ]. The elements covers all range countries expected in a typical undertaking. The leaden mark sheets show the subdivision, the class, elements with their weights and the range definition degrees every bit good as a column for component mark. The range definition degrees are 6 in figure runing from 0, which means non applicable, to 1, intending complete definition, 2 – minor lacks, 3 – some lacks, 4- major lacks and 5- incomplete or hapless definition. The weights were determined via workshops sing the comparative importance of each component to each other and its possible impact on the undertaking. Each component has a alone weight under each of the definition degrees ( degrees 1 – 5 ) , flat 0, being an component that is non applicable to the undertaking under consideration. If all degree 5 ( uncomplete range definition ) assigned weights are added together for the 70 elements of PDRI Industrial ( 64 for PDRI Building ) we would hold a entire leaden mark of 1000 points which is the worst instance. Similarly if all elements are wholly defined i.e at degree 1 definition, the add-on of the assigned leaden tonss for the 70 elements ( or 64 PDRI Buildings ) under this definition would give a sum of 70 points, which is the best instance. In a typical undertaking appraisal utilizing PDRI, the undertaking mark would be between 70 and 1000 points. It follows that the lower the undertaking score the better defined the undertaking is in footings of range.
“ A mark of 200 points or below utilizing this tool was shown to statistically increase the predictability of undertaking result. A sample of 40 undertakings utilizing the industrial version of the PDRI indicated that those undertakings hiting below 200 versus those hiting above 200 had:
Average cost nest eggs of 19 % versus estimated for design and building
Schedule decrease by 13 % versus estimated for design and building
Fewer undertaking alterations
Increased predictability of operational public presentation ”[ 24 ].
Table below is an infusion of a leaden mark sheet.
Table 2: Infusion of PDRI weighted score sheet ( Buildings )[ 25 ]
0 = Not Applicable 2 = Minor Deficiencies 4 = Major Lacks
1 = Complete Definition 3 = Some Deficiencies 5 = Incomplete or Poor Definition
A undertaking squad utilizing this tool reviews each of the 70 or 64 elements ( industrial or edifice ) along with its item description and compares them to the range definition bundle of the undertaking under consideration and scores the completeness of the element definitions. The mark for each component is recorded in the mark column and added to give the class mark and the class tonss are added to give the subdivision mark, subdivision tonss are added to give the undertaking PDRI mark. The lower the PDRI score the better the range definition. How existent marking is done will be discussed subsequently in this paper.
The PDRI has many benefits or utilizations. Harmonizing to Cho, C.S and Gibson, G. Jr, 2001, “ it can be used as:
A checklist that a undertaking squad can utilize for finding the necessary stairss to follow in specifying the undertaking range
A listing of standardised range definition nomenclature
An Industry criterion for evaluation the completeness of the undertaking range definition bundle during the planning procedure in order to mensurate advancement, buttocks hazard, and re-direct hereafter attempt.
A agency for undertaking squad participants to accommodate differences utilizing a common footing for undertaking rating
A tool that aids in communicating and alliance between proprietors and design contractors by foregrounding ill defined countries in a range definition bundle
A preparation tool for organisations and persons
A benchmarking tool for organisations to utilize in measuring completion of range definition versus the public presentation of past undertakings, in order to foretell the chance of success on future undertakings. ”[ 26 ]
This subdivision deals with the existent marking of a undertaking to find its degree of definition.
A undertaking squad meets at any point during the pre-project planning stage to carry on the appraisal. Amongst them is an independent facilitator who is sooner non portion of the undertaking squad but has good cognition of the undertaking. The undertaking squad and facilitator are provided with the range definition bundle of the undertaking ( scope statement, WBS, surveies, design sketches/drawings, specifications etc ) an un-weighted PDRI mark sheet, elaborate PDRI elements description and a leaden mark sheet sooner for merely the facilitator. It is non advisable to supply the leaden mark sheet to team members at the hiting session as they may be tempted to aim a peculiar mark. An un-weighted mark sheet for Buildings is shown in Appendix 2[ 27 ].
Each component and its description are read from the PDRI and this is compared to what is provided in the range definition bundle of the undertaking being assessed. See infusion of element description in Appendix 3[ 28 ]. The undertaking squad by consensus selects a degree of definition ( 0 to 5 ) that fits the component under consideration and checks the box under the definition degree that correspond to the component. The facilitator picks the leaden mark that corresponds with the checkered definition box ( in un-weighted mark sheet ) and transportations it to the mark column of the leaden mark sheet and that becomes the mark for the component. This procedure is repeated for all the PDRI elements. The elements score so derived are added together to give the class mark and the classs score added together give the subdivisions mark and subdivisions mark added gives the PDRI mark for the undertaking. “ The lower the entire PDRI mark, the better the undertaking range definition. Higher weights signify that certain elements within the range bundle deficiency equal definition and should be re-examined anterior to building paperss development. ”[ 29 ]
The PDRI 70 or 64 elements ( Industrial or Building ) are comprehensive descriptions of all range issues to be encountered in a undertaking. They are issues that need to be addressed in pre-project planning[ 30 ]. If Undertaking proprietors and design squads work with the PDRI elements, they are non likely to hold skips of critical elements in the undertaking range. It serves as their checklist in specifying the undertaking range.
With the elaborate description of the PDRI elements a installation proprietor is made cognizant of the extra information he needs to supply to guarantee undertaking success. When these are provided scope definition is improved.
One of the ways to better undertaking range definition is the usage of standardised work interrupt down construction ( WBS ) . An acceptable standardised WBS has been an semblance both in the Building and Industrial Sector. The hierarchy of PDRI subdivisions, classs and elements can organize the footing of a work dislocation construction ( WBS ) for proper range planning[ 31 ]. This can be adopted as a criterion topic to some amendments discussed subsequently in this paper.
The PDRI hiting procedure throws up points that are ill defined and therefore necessitate farther action. So instead that travel with uncomplete range into the following gate or executing stage, a better definition is sought and achieved before proceeding.
When making a PDRI appraisal equivocal statements or definitions are identified and clarified from relevant stakeholders, therefore bettering on the range definition.
The US Army Corps of Engineers in its ‘ Engineering and Construction Bulletin No. 2010-17 dated 29th July 2010 issued a guideline for the execution of Project Definition Rating Index. It states “ Get downing with the FY11 USACE managed MILCON Program, execution of PDRI will be a demand. ”[ 32 ]
The US Department of Energy besides issued a usher for the usage of PDRI for its Traditional Nuclear and Non- Nuclear Construction Projects, dated 22nd July 2010. It stated, “ This Guide assists persons and squads involved in carry oning appraisals of undertaking definition ( i.e. how good has front terminal planning been conducted to specify the undertaking range ) utilizing a numerical undertaking direction tool developed by the Construction Industry Institute ( CII ) that has been tailored for DOE usage. The tool is called the Project Definition Rating Index ( PDRI ) ”[ 33 ]
The PDRI has by and large been applied to traditional building undertakings that follow the design, command and concept attack. In this attack the design squad coatings their work and handover to the building squad. The building squad foremost interface is normally after the completion or partial completion of the elaborate designs. At this point the executing is ready to get down, and clip and budget are already firmed up. Any disagreements noticed between assorted drawings and skips and or add-ons at this point forth translate to bespeak for alteration orders. The consequence of hapless range definition begins to attest.
Construction today is traveling from the traditional attack described above to Integrated Project Delivery attack. Integrated Project Delivery ( IPD ) is a undertaking bringing attack that integrates people, systems, concern constructions and patterns into a procedure that collaboratively harnesses the endowments and penetrations of all participants to cut down waste and optimize efficiency through all stages of
design, fiction and building[ 34 ]. In an incorporate procedure hazard and benefits are jointly shared.
Cardinal demands in the IPD procedure are coaction and early engagement of assorted stakeholders. The proprietor, designer, applied scientists, contractor, subcontractors are assembled at the origin of the undertaking and they jointly work through the clients brief or statement of range, doing parts from their assorted subjects. This collaborative attack is continued through the assorted stages of the undertaking until the plants are completed and handed over to the proprietor.
Scope definition in this attack is a joint work devising room for varied and comprehensive thoughts ; points that would hold caused disagreements on site are thrown up and resolved. Those who normally asked for information elucidations at executing phase are all portion of the squad developing the range and are therefore able to indicate out those countries that are normally uncomplete in range definition utilizing the traditional building attack. In this attack the PDRI in its current signifier can be used as a benchmark for the completeness of the information that the elaborate design would be based on.
BIM is an Integrated Project Delivery Approach with practical theoretical accounts and informations bases. “ A edifice information theoretical account ( BIM ) is a digital representation of physical and functional features of a installation.
As such it serves as a shared cognition resource for information about a installation organizing a dependable footing for determinations during its life-cycle from origin onward ”[ 35 ]. The basic theoretical account is 3D but when sequence of building is added, it becomes a 4D theoretical account. When linked with gauging package it becomes a 5D theoretical account. The usage of 3D theoretical account in BIM enhances visual image and provides lucidity peculiarly for individuals with small accomplishments in reading building drawings. As an IPD procedure the undertaking stakeholders are assembled early in the planning procedure and working collaboratively are able to bring forth a batch of diverse and comprehensive range information within a short clip. Based on the generated information, the Architect, Engineers, and fiction contractors/subs develop their practical theoretical accounts which are shared with the squad members. By this attack countries of struggle are identified and fixed while still in the design development phase. In the traditional building attack these struggles are non identified until the executing stage and they by and large lead to alter orders and hence cost overproductions. BIM is based on information and information which must be organized, stored, retrieved, and transmitted through out the life rhythm of a undertaking. One of the pictured tools for forming information in BIM is the Omniclass Construction Classification System ( OminClass or OCCS ) . Harmonizing to the US National Institute of Building Sciences, OmniClass is applicable for forming many different signifiers of information of import to the NBIM Standard, both electronic and difficult transcript[ 36 ]. OmniClass has 15 tabular arraies for categorization of building information. For illustration building information can be classified by elements ( table 21 ) , merchandises ( table 23 ) , subjects ( table 33 ) etc. Entries in the OmniClass tabular arraies can be explicitly defined in the IFDLibrary one time and reused repeatedly, enabling dependable automated communications between applications – a primary end of NBIMS[ 37 ]. IFD Library is a sort of lexicon of building industry footings that must be used systematically in multiple linguistic communications to accomplish consistent consequences.
The PDRI can happen look in BIM if its 64 elements are aligned with the OmniClass elements table. But herein besides lies the restriction as the information in BIM can be organized with several other tabular arraies. Where this is the instance the PDRI will non be utile.
The PDRI is a range definition tool that can be used on any undertaking with enormous benefits as before highlighted. Its ‘ usage minimizes the effects of hapless range definition on a undertaking. However the use is still limited to America and some parts of Europe. Sing its part to project success I recommend that the tool be widely publicized for usage by a greater audience.
Many people already use one signifier of WBS or the other for range definition, the job nevertheless is the non standardisation of the WBS and its ‘ dictionary. OmniClass is turn outing to be a dominant categorization system whose elements can be used to organize the edifice blocks of a standard WBS alongside the IFD Library. It is recommended that the PDRI elements be updated and aligned with the OmniClasss elements to guarantee its continued utility in a fast changing building Industry. The PDRI is most suited for traditional building attacks. With modern undertaking bringing attacks such as IPD and BIM, the demand for the recommended alliance of PDRI elements with OmniClass can non be over emphatic. The PDRI in its current signifier has limited application in IPD and BIM environment.
The Project Definition Rating Index ( PDRI ) is a undertaking direction tool designed to increase the likeliness of undertaking success by bettering undertaking range definition, specifically by placing lacks in range definition early during the front-end planning procedure[ 38 ]. Analysiss of tonss from a undertaking appraisal utilizing the PDRI isolates ill defined elements of range for which farther action can be taken. When this farther action is taken it leads to betterment in the overall definition of the undertaking range. I hence recommend this tool for anyone who wants to better undertaking range definition and guarantee success in his undertaking.