成本上升因素现象的分类

施工项目成本上升

成本上升因素现象的分类

分析认为，从过去的三角剖分方法研究和访谈中，创建一个成本上升的原因分类，可以更好地理解到成本上升因素，是通过每个因素或因素的根源的推动力引起的。有了这样的认识，就能设计出策略来处理这些成本上升问题。在每个项目开发阶段的影响因素，主要分为内部因素和外部因素。导致成本上升和控制机构或业主内部的因素是直接控制现有的外机构或所有者分类外部的因素。演示顺序的因素，不应被视为暗示的影响。它总结成逻辑分区和分类汇总的因素并有助于在可视化的项目成本估算受到影响。需要重点注意的是，其中的因素指明与估计的劳动力和原材料成本的因素有关，但最值得注意的是其影响项目的范围和时机。

内部因素

内部因素是成本上升的主要因素，可直接被项目的赞助机构或所有者所控制。虽然许多内部因素成本在规划和设计阶段，可能会导致项目低估。主要的内部七大因素是有据可查的：偏差，交付/采购方式，项目进度的变化，工程和建筑的复杂性，范围的变化，范围逐渐扩大，贫困人口估计交配，此外，还有突发事件的不一致的应用程序的问题。一个项目的成本上升不只发生在规划和设计阶段，项目成本增长往往体现在施工期间。聚焦早期，内部因素会降低成本增长投标时间或减少在2006年期间建设安达等人。内部原因导致这种项目执行过程中低估成本，是工程项目管理不善造成的，这种文档设计是有缺陷的。更多的分析显示这些因素包括不应用权变，错误的执行，含糊不清的合同规定，以及合同文件冲突。每个这些因素单独或与他人相结合，可能会导致显著着的项目成本随着时间的推移而增加。

偏差是证明系统的倾向过于乐观的重点项目参数。它通常被视为故意低估项目成本，确保项目仍然在建设规划中。这种低估成本可能会出现的估计鉴定与机构或室的目标，保持施工方案。它可以是一种骄傲的结果，一种认为我们的机构比那些有问题的人更聪明的感觉。不会屈从于问题变化的范围，范围逐渐扩大，估算不佳，或任何其他因素。项目开发过程中，一些政府机构，立法机关的立法行为，建立了工程预算，预算是根据初步成本估算的。后来，如果执行机构的估计是高于项目预算的，这个项目就不能通过。因此，工程师和机构感到了压力，就以一种乐观的态度来估计了。例如1998年的阿肯哲和菲舍尔等。1998年康登和哈曼，1970年的Hufschmidt 和日兰。

送货或采购方式影响了机构或雇主和建设人员的风险划分，而当风险转移到一个谁也无法控制的特定风险时，项目的成本可能会增加。有关决定哪些项目的交付方式，如设计 - 招标 - 建造，设计，建设，或建立经营 - 转让和采购方法，如，低价中标，最佳值，或资格的选择会影响转让项目的风险。除了风险分配的问题，缺乏经验与交付方式或采购方式也导致低估项目成本。许多机构和业主正在寻求降低项目的时间表，以提供更多需要加速的项目需求，但加速时间表的实现是要代价的。虽然最终结果采用不同的采购的方法应该是有利的，但是一些沉痛的教训也应该适当的分配，风险和每一个新的的承包方法都需要机构或业主的响应、期望。

外部因素

外部成本上升的因素，机构或所有者对这些因素的影响已经很少甚至没有直接控制。然而，在估算项目成本时，仍需要考虑他们。在项目发展的规划和设计阶段中的外部因素，如当地政府关注和需求，扰动的速度信息，范围变更，范围逐渐扩大，以及市场条件可能会导致项目成本的低估。在项目建设过程中的外部因素，如当地政府的关注和需求，市场条件，不可预见的事件，和不可预见的条件都会造成项目成本的增加。对于此类可能性事件必须做好估计的考虑。再次必须认识到，这些元素中的每一个可以单独地或组合地采取行动都会造成重大项目的成本增加。当地的关切和要求通常包括缓解对周围社区以及协商范围变更或新增项目的影响。机构/所有者往往需要减轻对当地的社会环境，以及自然环境有负面影响的建设项目。措施可包括项目设计，走线，及进行施工作业。这些步骤往往采取安抚当地的居民，企业主，和环保团体等手段。在早期往往是未知的所需的住宿项目开发阶段。有许多采用“激烈”措施的例子，以适应当地的政府与公民关系以及民族关系。最显著的两个例子是旧高速公路工程在犹他州和马萨诸塞州的大挖掘。未知的土壤条件会影响开挖、压实、基础结构，受污染的土壤也会出现，现在的实用程序有很多问题，一般出现在错误的描述或者描述错误的图纸中，只不过这项技术还在规划和设计阶段，不过它也会显著增加项目成本。市场条件下的宏观环境的变化会影响一个项目的成本，尤其是大型工程项目。通常只有大型承包商或承建商组可以进行大型工作，甚至获得一个大型项目的键合。一个项目的规模会影响该项目和机构/所有者接收工作的投标数量的竞争。通常情况下， 大项目得风险要大得多，无论是对业主还是承包商，这些都会影响项目成本。。市场的不准确的评估会导致不正确的项目成本估算。市场条件在执行阶段和规划阶段对项目成本都会有类似的影响。不可预见的事件是无法预料到的，而且通常是不能由项目业主控制的，这可能是一个事件，例如oods ，飓风，龙卷风或其他天气相关的事件。通常，这些事件被称为“上帝的行为”，这些行为会带来建设停滞，已经遭遇到的一些工作销毁，造成了需要大量的返工或维修。由第三方进行的活动控制也是不可预见的，包括恐怖袭击，罢工，和金融或商品市场的变化，这些行动将会造成项目和项目成本的严重性破坏。

;

Construction Project Cost Escalation Factors Jennifer S. Shane, A.M. ASCE

1; Keith R. Molenaar, M.ASCE2; Stuart Anderson, M.ASCE3; and

Cliff Schexnayder, Dist.M.ASCE

Cost Escalation Factor Classication

T he triangulat ion analysis considered methodologies from past

studies and interviews to create a categoriz at ion for the causes of

cost escalation. A better understanding of the cost escalation fac-

t ors is achieved through understanding the forces driving each

fact or or where the factor originates. With this understanding it is

p ossible to design strat egies for dealing wit h these cost escalation

factors.

T he factors that affect the estimat e in each project develop-

ment phase are by nature internal and external. Factors that con-

t ribut e to cost escalation and are controllable by the agency/owner

are internal, while facto rs existing outside the direct control of the

agency /owner are classied as external. This arrangement of fac-

t ors is shown in Table 2. The presentat ion order of the factors

should not be taken as suggesting a level of inuence. Table 2 is

const ruct ed to provide an over arching summary of the factors. It

summariz es the factors into logical divisions and classications

and helps in visualizing how project cost estimat es are affected. It

is import ant to note that one of the factors point s to problems with

est imat ion of labor and material cost, but most of the factors point

t o “inuences” that impact project scope and timing.

Internal

Int ernal factors are cost escalation factors that can be directly

cont rolled by the project ’s sponsoring agency/owner. While nu-

merous internal factors can lead to underestimat ion of project

costs during the planning and design stages of development seven

p rimary internal factors are well documented: bias, delivery/

p rocurement approach, project schedule changes, engineering and

const ruct ion complexit ies, scope changes, scope creep, poor esti -

mat ing, and additionally there is the issue of inconsistent appli -

cat ion of contingencies. Cost escalation does not only occur

during the planning and design phases of a project. Project cost

growt h often manifests itself during construct ion. Focusing early

on internal factors will reduce cost growth at bid time or during

const ruct ion Anderson et al. 2006 . Internal factors that lead to

t he underestimat ion of project costs during the execution of a

p roject stem from poor project management and defective design

document s. More specically , these factors can include inconsis-

t ent applicat ion of contingency , faulty execution, ambiguous con-

t ract provisions, and contract document conicts. Each of th ese

fact ors separat ely or in combination with others can cause signi-

cant project costs increases over time.

Bias is the demonstrat ed systemat ic tendency to be overopti -

mist ic about key project paramet ers. It is often viewed as the

p urposeful underestimat ion of project costs to ensure a project

remains in the construct ion program. This underestimat ion of

costs can arise from the estimat ors’ identicat ion with the agen-

cy ’s or rm’s goals for maintaining a construct ion program. It can

also be the result of pride and a feeling that our agency is smarter

t han those others that had problems and will not succumb to the

issues of scope changes, scope creep, poor estimat ing, or any of

t he other factors.

T he project development process for some government agen-

cies is such that the legislature establishes a project budget by

legislat ive act and that budget is based on preliminary cost esti -

mat es. Later, if the executing agenci es estimat e is higher than

t he budget, the project cannot be let. As a result, engineers and

agenc ies feel the pressure to estimat e with an optimist ic attit ude

Akinci and Fischer 1998; Condon and

Harman 2004; Hufschmidt and Gerin 1970;

Pickrell 1992 .

Delivery /procurement approach effects the division of risk be-

t ween the agency/owner and the construct ors, and when risk is

shift ed to a party who is unable to control a specic risk, project

cost will likely increase. The decision regarding which project

delivery approach, e.g., design-bid-build, design-build, or build-

op erat e-t ransfer and procurement methodology e.g., low bid,

best value, or qualications based selection affects the transfer of

p roject risks. In addition to the question of risk allocation, lack of

exp erience with a delivery method or procurement approach can

also lead to underestimat ion of project costs. Many agencies and

owners are looking to reduce project schedules to deliver much-

needed project s quickly but accelerated schedules are only

achievable at a cost. While the end results of apply ing different

p rocurement approaches should be benecial, some hard lessons

have been learned regarding the prop er allocation of risks and

what each new contract ing method entails, in terms of agency/

owner responsiveness, expect at ions, and time Harbuck 2004; New Jersey Depart ment of Transp ort at ion 1999; Parsons Brinck-

erhoff Quade & Douglas, Inc. 2002; Science Applicat ions Inter -

nat ional Corporat ion 2002; Weiss 2000 .

Project schedule changes, part icularly extensions, caused by

budget constraints or design challenges can cause unanticip at ed

increases in ination cost effects even when the rate of ination is

accurat ely predict ed. Agencies/owners must think in terms of the

t ime value of money and recognize that there are two components

t o the issue: 1 the ination rate and 2 the timing of the expen-

dit ures. Many agencies and owners have xed annual or biannual

budget s and project schedules must often be adjusted to ensure

t hat project funding is available for all projects as needed. Esti -

mat ors frequently do not know what expendit ure timing adjust-

ment s will be made Board on Infrastruct ure and the Construct ed Environment 2003; Booz Allen & Hamilt on Inc. and DRI/

M cGraw-Hill 1995; Callahan 1998; Hufschmidt and Gerin 1970; GAO 1999; Semple et al. 1994; Touran et al. 1994 .

Engineer in g and construct ion comple xit ies caused by the p roject ’s location or purpose can make early design work very challen gin g and lead to internal coordination problems and p roject component errors. Internal coordination problems can in- clude conicts or problems between the various disciplines in- volved in the planning and design of a project. Construct ability p roblems that need to be addressed may also be encountered as t he project develops. If these issues are not addressed appropri - at ely , cost increases are likely to occur Board 2003; The Big Dig: Key facts about cost, scope, schedule, and management 2003; Booz Allen & Hamilton Inc. and DRI/McGraw-Hill 1995; Calla- han 1998; GAO 2003; Hufschmidt and Gerin 1970; GAO 1997, 1999, 2002; Touran et al. 1994 .

Scop e changes, which should be controllable by the agent/ owner management, can result in underestimat ion of project cost s. Such changes may include modicat ions in project con- st ruct ion limits, alterat ions in design and/or dimensions of key p roject items such as adjustments in type, size, or location of p roject component s, as well as other increases in project elements Board on Infrastruct ure and the Construct ed Environment 2003; Booz Allen & Hamilton Inc. and DRI/McGraw-Hill 1995; Calla- han 1998; Chang 2002; Harbuck 2004; Hufschmidt and Gerin 1970; Mackie and Preston 1998; GAO 1999; Merrow 1988; Semp le et al. 1994; Touran et al. 1994 .

Scop e creep is the tendency for the accumulation of many minor scope changes to increase project costs. While individual scop e changes may have only minimal cost impacts, the accumu- lat ion of these minor changes, which are often not essential to the int ended function of the facility, can result in a signicant cost increase over time. Many of these minor changes are real needs t hat are recognized as more is known about the project but others are often only nonessential additions. Projects often seem to grow nat urally as the project progresses from inception through design develop ment to construct ion. These changes can often be attrib- ut ed to the different needs of the traveling public or environmen- t al compliance in the area being served Akinci and Fischer 1998; Board on Infrastruct ure and the Construct ed Environment 2003; Booz Allen & Hamilton Inc. and DRI/McGraw-Hill 1995; Calla- han 1998; Chang 2002; Harbuck 2004; Hufschmidt and Gerin 1970; Mackie and Preston 1998; GAO 1999; Merrow 1988;

Semp le et al. 1994; Touran et al. 1994 .

Poor estimat ing can lead to project cost underestimat ion. Es- t imat e documentat ion must be in a form that can be understood, checked, veried, and corrected. The foundation of a good esti - mat e is the formats, procedures, and processes used to arrive at t he cost. Poor estimat ion includes general errors and omissions from plans and quantit ies as well as general inadequacies and p oor performance in planning and estimat ing procedures and t echniques. Errors can be made not only in the volume of material and services needed for project complet ion but also in the costs of acquiring such resources Arditi et al. 1985; Booz Allen & Hamil- t on Inc. and DRI/McGraw -Hill 1995; Chan g 2002; Harbuck 2004; Hufschmidt and Gerin 1970; Merrow 1988; Pickrell 1992 . Inconsist ent applicat ion of contingencies causes confusion as t o exactly what is included in the line items of an estimat e and what is covered by contingency amounts. Contingency funds are typ ically meant to cover a variety of possible events and problems t hat are not specically identied or to account for a lack of

p roject denition during the prep arat ion of early planning or pro- gramm ing estimat es. Misuse and failure to dene what costs con- t ingency amounts cover can lead to estimat e problems. In many cases it is assumed that contingency amounts can be used to cover added scope and planners seem to forget that th e purp ose of the cont ingency amount in the estimat e is to cover lack of design denit ion. Agencies and owners run into problems when the con- t ingency amounts are applied inapprop riat ely. Inconsistent appli - cat ion of contingency can be both an internal fact or contribut ing t o underestimat ion during the planning and preliminary design st age and a contribut or to cost overruns during nal design or const ruct ion phases of the project. During project construction, cont ingency funds are inapprop riat ely applied to const ruct ion overruns and then not available for their intended purp ose Noor and Tichacek 2004; Ripley 2004 .

Faulty execution by an agency/owner in managing a project is one factor that can lead to project cost overruns. This factor can include the inability of the agency’s/owner’s represent at ives to make timely decisions or actions, to provide information relative t o the project , and failure to appreciat e construct ion difculties caused by coordination of connecting work or work responsibili - t ies Board on Infrastruct ure and the Construct ed Environment 2003; Callahan 1998; Chang 2002; Touran et al. 1994 . Ambiguous contract provisions

dilut e responsibility and cause

misunderst anding between an owner and project design and con-

st ruct ion contract ors. Providing too little information in the p roject documents can lead to cost overruns during the execution of the project. When the core assumptions underlying an estimat e are confused by ambiguous contract provisions forecast accuracy cannot be achieved Callahan 1998; Chang 2002; Harbuck 2004; M ackie and Preston 1998; Touran et al. 1994 .

Cont ract document conicts lead to errors and confusion while bidding and later during project execution they cause change or- ders and rework Callahan 1998; Chan g 2002; Harbuck 2004; M ackie and Preston 1998; Touran et al. 1994 .

External

Ext ernal cost escalation factors are those factors over which the agency /owner has little or no direct control over their impact. However, the agency/owner needs to consider them when esti - mat ing project costs. During the planning and design phase of p roject development external factors such as local government concerns and requirements, uctuat ions in the rate of ination, scop e change, scope creep, and market conditions can lead to underest imat ion of project costs. During project construct ion ex- t ernal factors such as local government concerns and require- ment s, market conditions, unforeseen events, and unforeseen condit ions can be responsible for increases in project cost. The p ossibility of such incidents must be considered during estimat e p rep arat ion. Again it must be recognized that each of these ele- ment s can act separat ely or in combination with others to cause signicant project cost increases.

Local concerns and requirements typically include mitigat ion of project impacts on the surrounding community as well as ne- got iat ed scope changes or additions. Actions by the agency/owner are often required to alleviate perceived negative impacts of con- st ruct ion on the local societal environment as well as the natural environment. Measures may include but are not limited to intro - ducing changes to project design, alignment, and the conduct of const ruct ion operat ions. These steps are often taken to appease t he local residents, business owners, and environment al groups. T he required accommodation is often unknown during the early st ages of project development. There are a multit ude of examples of “drast ic” measures that are taken to accommodate local gov- ernment and citiz en concerns as well as national concerns with t wo of the most notable examp les being act ions during the Legacy Highway project in Utah and the Big Dig in Massachu - sett s In Utah environment concerns raised by the community p lay ed a major role in delaying the project and increasing the cost. In Massachusett s the community demanded a signat ure

bridge across the Charles River. The resulting cable-st ay ed bridge wit h Y-shaped towers added signicantly to the projects cost. Local Concerns and Requirements can affect project costs dur- ing the execution phase. Similar to the effects during the planning and design phases, mitigat ion actions imposed by the local gov- ernment , neighborhoods, and businesses as well as local and na- t ional environmental groups during the construct ion of a project can extend the project duration affecting ination allowances or add direct cost. By not anticip at ing these changes, agencies/ owners can be plagued by project cost increases Board on Infra- st ruct ure and the Construct ed Environment 2003; Booz Allen & Hamilt on Inc. and DRI/McGraw -Hill 1995; Cal lah an 1998; Chan g 2002; Daniels 1998; Harbuck 2004; Hudachko 2004; “Lega cy Parkway: History of the Legacy Parkway.” 2004; M ackie and Preston 1998; GAO 1999; Merrow 1988; Parsons Brinckerhoff Quade & Douglas, Inc. 2002; Pearl 1994; Sawyer 1952; Schroeder 2000; “Summ ary of independent review commit- t ee ndings regardin g Woodrow Wilson Bridge superst ruct ure cont ract ” 2002; Touran et al. 1992 1994; Woodrow Wilson Bridge p roject superst rucy ure contract BR-3 : Review of the engineer’s est imat e vs. the single bid 2002 .

Effect s of ination is a key factor in the underestimat ion of costs for many projects. The time value of money can adversely affect projects when 1 project estimat es are not communicated in year-of-const ruct ion costs, 2 project complet ion is delayed and therefore the cost is subject to ination over a longer duration t han anticip at ed, and/or 3 the rate of ination is greater than ant icip at ed in the estimat e. Industry has varying views regarding how ination should be accounted for in project estimat es and in budget s. In the case of projects with short development and con- st ruct ion schedules, the effect of ination is usually minor; how- ever project s having long development and construct ion durations can encounter unanticip at ed inationary effects. The cost esti- mat es for the Big Dig in Boston are an examp le of ination ef- fect s. The Big Dig est imat e was originally developed in 1982 based on the Federal Highway Administrat ion guidelines stat ed in t he Interst at e Cost Estimat e manual. The procedures called for the exclusion of inationary factors. Ination is a large port ion of the cost overruns experienced on the project Akinci and Fischer 1998; Arditi et al. 1985; Board on Infrastruct ure and the Con- st ruct ed Environment 2003; Booz Allen & Hamilton Inc. and DRI/McGraw -Hill 1995; Hufschmidt and Gerin 1970; Merrow 1988; Pickrell 1992; Touran et al. 1994 .

Scope chang es

, which are not controllable by the owner, can

lead to underestimat ion of project cost escalation. In California t he new east span bridge between Oakland and Yerba Buena Is- land was the responsibility of the California Depart ment of Trans- p ort at ion Caltrans . The legislation act that funded the bridge p laced it under the jurisdiction of the Met ropolit an Transportat ion Commission MTC . Based on its rights by jurisdiction the MTC select ed an asymmet rical self-anchored suspension bridge design wit h a single tower. This was a fundamentally different bridge t han the one Caltrans had envisioned resulting in large cost in- creases. Agencies have serious estimat e inaccuracies when scope changes are imposed externally Board on Infrastructure and the Const ruct ed Environment 2003; Booz Allen & Hamilton Inc. and DRI/McGraw -Hill 1995; Callahan 1998; Chang 2002; Harbuck 2004; Hufschmidt and Gerin 1970; Mackie and Preston 1998; GAO 1999; Merrow 1988; Semple et al. 1994; Touran et al. 1994 .

Scop e creep is similar to changes in scope; however, this is the effect of the accumulation of multip le minor scope changes. Project s seem to often grow naturally as the project progresses from incept ion through development to construct ion. These changes can often be attribut ed in the case of transp ort at ion and many other types of project s to the changing needs or growth of t he pop ulat ion in the area to be served. Minor changes can often occur in response to local agency or citiz en requests. Akinci and Fischer 1998; Board on Infrastructure and the Constructed Envi- ronment 2003; Booz Allen & Hamilton Inc. and DRI/McGraw - Hill 1995; Calla han 1998; Chang 2002; Harbuck 2004; Hufschmidt and Gerin 1970; Mackie and Preston 1998; GAO 1999; Merrow 1988; Semple et al. 1994; Touran et al. 1994 . M arket conditions or changes in the macro environment can affect the costs of a project , part icularly large proje cts. Often only large contract ors or groups of contract ors can work or even obtain bonding for a large project. The size of the project affects com- p et it ion for a project and the number of bids that an agency/owner receives for the work. Typically , the risks associated with large p roject s are much greater, both for the owner and contractor, and t hat affects project costs. Inaccurate assessment of the market condit ions can lead to incorrect project cost estimat ing. Market condit ions affect the project costs during the execution phase similar to the effects during the planning phase. Changing market condit ions during the construct ion of a project that reduces the number of bidders, affects the labor force, and other related ele- ment s can disrupt the project schedule and budget Board on In-

frast ruct ure and the Construct ed Environment 2003; Booz Allen & Hamilton Inc. and DRI/McGraw -Hill 1995; Callahan 1998; Chan g 2002; Mackie and Preston 1998; GAO 1999; Merrow 1988; Pearl 1994; Sawy er 1952; “Summary of independent re- view commit t ee ndings regardin g the Woodrow Wilson Bridge sup erst ruct ure contract ” 2002; Touran et al. 1994; Woodrow Wil- son Bridge project bridge superst ruct ure contract BR-3 : Review of the engineer’s estimat e vs. t he single bid 2002 .

Unforeseen events are unanticip at ed and typically not control - lable by a project owner; these could be occurrences such as oods, hurricanes, tornadoes, or other weather related incidents. Typ ically these are called “act s of God.” These acts can bring const ruct ion to a standst ill and have been known to destroy work creat ing the need for extensive rework or repair. Events controlled by third part ies that are also unforeseen include terrorism, strikes, and changes in nancial or commodity markets. These actions can have devastat ing results on project s and on project costs Akinci and Fischer 1998; Arditi et al. 1985; Callahan 1998; Chang 2002; Hufschmidt and Gerin 1970; Merrow 1988; Semple et al. 1994; T ouran et al. 1994 .

Unforeseen conditions

are notorious for causing cost overruns.

Unknown soil conditions can effect excavation, compact ion, and st ruct ure foundations. Contaminat ed soils may be present. Utili - t ies are often present that are not described or described incor- rect ly on the drawings. There are a multit ude of problems that are simp ly unknown during the planning and design phases and which can increase project cost when they become apparent during construct ion Akinci and Fischer 1998; Arditi et al. 1985; Callah an 1998; Harbuck 2004; Hufschmidt and Gerin 1970; M errow 1988; Semple et al. 1994; Touran et al. 1994