Construction Delay
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International Journal of Project Management 18 (2000) 51±59 www.elsevier.com/locate/ijproman
Construct Construction ion delay: delay: a quantitat quantitative ive analysis analysis Ayman Ayman H. Al-Moma Al-Momani ni Mu'tah University, Civil Engineering Department, Karak, Mu'tah, P.O. Box 7, Jordan
Abstract
Avoiding construction claims and disputes requires an understanding of the contractual terms and causes of claims. The dual underlying theme of this paper is to investigate the causes of delays on 130 public projects in Jordan and to aid construction managers in establishing adequate evaluation prior to the contract award using quantitative data. Projects investigated in this study included residential, oce and administration administration buildings, school buildings, buildings, medical centers and communication communication facilities. facilities. Result Resultss of this this study study indicat indicates es the main causes causes of delay delay in construc construction tion of public public project projectss relate relate to designe designers, rs, user user changes changes,, weathe weather, r, site site conditi conditions, ons, late late delive deliveries ries,, economi economicc conditi conditions ons and increa increase se in quantit quantity. y. The presenc presencee of these these factor factorss have have an impact on the successful completion of the projects at the time contractually speci®ed. The ®ndings suggest that special attention to factors identi®ed in this study will help industry practitioners in minimising the risk of contract disputes. # 1999 Elsevier Science Ltd and IPMA. All rights reserved. Keywords: Construction management; Project planning; Construction delay; Dispute
1. Introduction
1.1. Previous work
A vital section speci®ed in the construction contract is the performance period or time of project execution, which which is establ establish ished ed prior prior to biddin bidding. g. The The succes successfu sfull execut execution ion of constru constructi ction on projec projects ts and keepin keeping g them them with within in esti estima mate ted d cost cost and and the the pres prescr crib ibed ed sche schedu dule less depend depend on a method methodolo ology gy that that requir requires es sound sound enginengineering eering judgme judgment. nt.[1] [1] The constru constructi ction on sector sector is one of the vital sectors in the development process of Jordan. The government contributes to the development of the constructio construction n industry industry in several several ways. However, However, there are limitati limitations ons and even even draw draw backs backs to these these eorts eorts.. The time time requir required ed to comple complete te constru constructi ction on of public public projects is frequently greater than the time speci®ed in the contra contract. ct. These These `overru `overruns' ns' or time time extensi extensions ons are granted for many reasons, such as designer changes or erro errors, rs, user user chang changes es,, weat weathe herr and and late late deli delive veri ries. es. Curr Curren entt cons constru truct ctio ion n proj projec ects ts are are comp comple lex x eort eortss requir requiring ing the suppor supportt of the design design and constru constructi ction on profess profession ion.. Therefo Therefore, re, a realis realistic tic time time for projec projectt execut ecutio ion n will will decr decrea ease se the the poss possib ibil ilit ity y of disp disput utes es between state agency and the contractors.
A great deal of information concerned with project delay and overruns may be found in the literature. The increas increased ed interes interestt in constru constructi ction on overru overruns ns is due, due, in part, to eorts by the government to reduce construction delays. There has been a considerable and continued intere interest st in the eect eect of constr construct uction ion delays. delays. The information available is diverse and widespread. Many constructio construction n management management books[2±6] books[2±6] have minimum minimum cove covera rage ge on cons constr truc ucti tion on dela delays ys.. Al-M Al-Mom oman ani[ i[7] 7] descri describe be the var variou iouss elemen elements ts of cost cost upon upon indivi individua duall public projects but does not deal speci®cally with construction delays. Assaf Ass af and AlAl-kha khali lil[8 l[8]] outlin outlinee the main main causes causes of delay delay in large large buildi building ng projec projects ts and their their relati relative ve imimportance. They found that 56 causes of delay exist in Saudi construction projects. According to the contractors tors survey surveyed ed the most most importa important nt delay delay factor factorss were were preparation and approval of shop drawings, delays in contractor's contractor's progress, payment payment by owners owners and design change changes. s. The archit architect ectss and engine engineers ers view view were were cash cash problems during construction, the relationship between subcontracto subcontractors rs and the slow decision decision making making process process
0263-7863/99/$20.00 # 1999 Elsevier Science Ltd and IPMA. All rights reserved. PII: S0263-7863(98)00060-X
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A.H. Al-Momani Al-Momani / International International Journal of Project Management Management 18 (2000) 51±59
Table 1 Summary of project information Classi®cation
Poor design
Change orders
Weat he her
Site condition
Late delivery
Economic condition
Increase in quantity
No delay
Total
House Oce School Medical centers Communication facilities Total
4 8 10 6 4 32
1 5 8 4 2 20 20
3 4 6 2 1 16
1 2 5 0 0 8
0 1 4 3 2 10
0 4 2 2 0 8
2 5 3 1 1 12
3 5 14 2 0 24
14 34 52 20 10 130
of the owner. The owners agree that the design errors, labor shortages and inadequate labor skills are important delay factors. Hancher and Rowings,[1] for example, provide a concise summary of the methodologies used by transportation agencies to establish the contract duration used for highway construction projects, and also provides a schedule guide for ®eld engineers during construction. Similarly, Chalabi and Camp[10] conducted a review on project delays in developing countries during planni planning ng and constru constructi ction on stages stages.. In their their study study they they found that the delay and cost overruns of construction projects are dependent entirely on the very early stages of the project. Fereig and Qaddumi[11] in their study on the construction experience of the Arabian Gulf demonstrate the various components of the planning, controlling ling and and prod produc ucti tivi vity ty on cons constru truct ctio ion n dela delay. y. Thei Theirr primary purpose is to alert the reader to the deviation from the project plans. Wilson[9] examined the role of the owner and architect/engineer's roles in the prevention and resolution of const constru ruct ctio ion n clai claims ms.. Wi Wils lson on also also summ summar aris ised ed the the caus causes es of cons constru tructi ction on clai claims ms whic which h incl includ ude: e: extr extra a work, project delays and acceleration, lack of management, limited site access and change in work schedule. Despit Despitee the necess necessity ity for such such resear research, ch, li little ttle work work has been described in the literature concerning public projects, specially in Jordan. The previously proposed factor factorss contri contribut buting ing to constr constructi uction on delay delay were were frefrequentl quently y observ observed ed in publi publicc projec projects. ts. The actual actual frefrequency and magnitude of these factors is not known, which has proven to be a serious and very expensive problem to Jordan's construction industry.
publ public ic proj projec ects ts constr construc ucte ted d in die diere rent nt regi region onss of Jord Jordan an duri during ng the the peri period od of 1990±9 1990±97. 7. The The data data was was found in contract ®les of several state agencies. Data collected were of 5 kinds of public projects: residential hous houses es of publ public ic ®gur ®gures es,, oce oce and and admi admini nist stra rati tive ve buildings, buildings, school buildings buildings,, medical medical centers centers and communication munication facilities. facilities. The performance performance and construcconstructio tion of thes thesee proj projec ects ts were were reco recogn gnis ised ed as bei being unsati unsatisfa sfactor ctory y to many many ocial ocials, s, and ass assent ented ed to the study in order to have hard evidence as to the nature of the problems. This study will summarise the results of this research based on actual construction times experien perienced ced by public public projec projects. ts. The data data collec collectio tion n was to investigate the reasons related to construction delay and overruns:
1.2. Research design and objectives
School buildings
52
Medical centers
20
Communication facilities
12
The objective of this study is to determine the causes and the level of time extension of public projects and to aid construction managers in establishing adequate evaluation prior to the contract award using quantitative data. The key task is to design research so that the informatio information n obtained obtained permits permits the assessment assessment of their impact. Therefore, the best approach to assessing these potentials is to adopt randomly selected samples. The sampling sampling population population was established established by selecting selecting 130
. .
Planned Planned duration duration of contract; contract; Actual completion date;
Table 2 Descriptive statistics of the public projects Number Number of of Duratio Duration n Project categories
House
projects
14
Oce Oce and adminis nistra trativ tive buil uildin dings 34
Plan lanned ned
Actu ctual
max. 450
832
min. mean mean SD max. min. mean mean SD max. min. mean mean SD max. min. mean mean SD max. min. mean mean SD
66 297.2 297.2 19 192.9 2.9 751 67 442.2 442.2 15 152.9 2.9 928 225 467.5 467.5 14 141.1 1.1 904 193 444.5 444.5 23 231.7 1.7 410 41 230 308.2 308.2 59.9
75 7 5 221.4 221.4 102 102.3 750 750 100 354.6 354.6 120 120.0 660 150 395.4 395.4 129 129.7 720 90 313.5 313.5 162 162.6 360 195 268.2 268.2 58.0
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. y a l e d f o s e s u a C . 1 . g i F
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A.H. Al-Momani Al-Momani / International International Journal of Project Management 18 (2000) 51±59
Fig. 2. Scatter plot of actual time Y versus planned time X for general model of public projects.
. . . . . . . .
Design changes; Disputes; Noti®cation of extra work; Date of notice to proceed; Delay encountered during construction; Con¯ict of the drawings and speci®cations; Time extensions; Late delivery of materials and equipment.
poor poor design design,, change change orders, orders, weathe weather, r, site site condit condition ions, s, late late deli delive very ry,, econ econom omic ic cond condit itio ions ns and and incr increa ease se in quanti quantity. ty. A breakd breakdown own of the projec projects ts by these these parparameters is graphically illustrated in Fig. 1. The overall delays delays were in 106 out of 130 (81.5%) (81.5%) projec projects. ts. The main causes for delays were poor design in 32 projects (24.6%), while the second cause was the change orders in 20 proj projec ects ts (15. (15.4% 4%). ). The The site site cond condit itio ions ns and and the the economic conditions were the least cause of delay and were found in 8 projects.
2. Discussions Discussions
2.1. Planned and actual duration
The data were entered into Excel 5 where all analysis and diagrams were developed. The ®rst step was to explore the parameters as to causes of delay. To this eect eect,, para parame mete ters rs were were de®n de®ned ed and and cons constr truc ucte ted d in Table 1 for public projects. These restrictions create a sample sample with with 130 projec projects. ts. The table table provid providee freque frequenncies cies for each each parame parameter ter in ®ve diere dierent nt constru constructi ction on categ categori ories es.. Ma Many ny proj projec ects ts were were dela delaye yed d for for many many reason reasons. s. All extens extension ionss to the planne planned d schedu schedule le were were considered as delays. The major causes identi®ed were:
The mean actual duration for all public projects was 426. 426.6 6 days days,, and and a stand standar ard d devi deviat atio ion n of 137 137 days days.. While the planned duration for the same projects was 343.1 days in mean, with a standard deviation of 137.4 days. days. The mean, mean, maximu maximum, m, minim minimum um and standa standard rd deviation for the planned and actual time were compute puted d as show shown n in Tabl Tablee 2 for for ®ve ®ve proj projec ectt clas classi si®®cations. It can be noticed that the actual time for each type of project vary considerably. This is illustrated by large dierences between the means of the planned and
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A.H. Al-Momani Al-Momani / International International Journal of Project Management Management 18 (2000) 51±59
Fig. 3. Scatter plot of actual time versus planned time of the housing model.
actual times and the high values of standard deviation. For instance, the mean planned time for school buildings varied from 395.4 days to an actual of 467.5 days, whil whilee the the oce oce and and admi admins nstr trati ative ve buil buildi ding ngss vari varied ed from 354.6 planned days to 442.2 actual days. The implic plicati ation on is ther therefo efore re,, that that on aver averag agee duri during ng the the sample sample period, period, the planne planned d and actual actual durati duration on was upwa upward rd sl slop opin ing. g. Stand Standar ard d devi deviat atio ion n are are repo report rted ed which which sugges suggestt that that the variance variance of the actual actual time is consid considera erably bly greate greaterr than than that that of the planne planned d time, time, with with the the vari varianc ancee of the the actu actual al time time bein being g appr approx oxiimately 29 444.67 days and the variance of the planned time being approximatel approximately y 18 894 days. A mathemat mathematica icall struct structure ure was studie studied d by diere dierent nt functi functions ons that that ®ts the data, data, which which indica indicated ted that that the si simp mple le line linear ar regr regress essio ion n appe appear arss to be appr approp opri riate ate for for this this type type of prob proble lem. m. The The spec speci® i®ca cati tion on of our our mode modell is deter determi mine ned d by one one inde indepe pend nden entt vari variab able le whic which h si sign gni® i®ca cant ntly ly expl explai aine ned d vari variat atio ions ns in the the reresponse sponse var variab iable. le. Correla Correlatio tion n coeci coecient entss were were used used for for scree screeni ning ng the the vari variab able les. s. Seve Severa rall stat statis isti tical cal tests tests were were cond conduc ucte ted. d. Each Each of thes thesee was was perf perfor orme med d at 99% con®denc con®dencee level. level. It was assumed assumed that that both both the actual actual and planne planned d times times distri distribut bution ionss were were normal normal and independent independently ly distributed. distributed.
3. Tests and results
Simple Simple linear linear regress regression ion develo develops ps an equati equation on that that descri describes bes the relati relations onship hip betwee between n two var variab iables les.. In this case the equation takes the form of: Y b0 b1 X X e
In this model Y is the dependent variable, the parameters, b0 and b1 are are the the coe coeci cien ents ts whic which h are are unknow unknown n and are to be estima estimated ted.. X is the indepe indepenndent dent var variab iable, le, and e is a rand random om error error whic which h is the the amount of variation in Y not accounted for by the linear relati relations onship hip.. The theore theoretic tical al models models are derive derived d and explained in the following. For For a compa compari riso son n of the the actu actual al and and plan planne ned d time time distribution, the equation developed for overall public projects is: Y 82X87 1X0016x R2 0X64 DXWX
1X58
231X25
R
0X80 SXEX 102X8
F À value
1
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A.H. Al-Momani Al-Momani / International International Journal of Project Management 18 (2000) 51±59
Fig. 4. Scatter plot of actual time versus planned time of the oce building model.
The correl correlati ation on coeci coecient ent for this this relati relations onship hip is 0.80 0.8 0 indica indicatin ting g that that the distri distribut bution ion of planne planned d time time mirrors the actual time with a high degree of accuracy. The calcul calculate ated d F is 231 231.25 .25,, the higher higher absolu absolute te val value ue of the F-statistics reported may re¯ect the observation that that are are powe powerfu rfull pred predic icto tors rs of the the meas measur ured ed data data.. Therefore, true linearity exists in the developed model. Comp Compar arin ing g samp sample le mean meanss to test test the the agre agreem emen entt betwee between n the two distri distribut bution ion was employ employed. ed. In this this case the t-statistic is 9.28 which is much larger than tvalue val ue of 1.9 1.97, 7, giv giving ing further further proof proof of the agr agreem eement ent betwee between n the two distri distribut bution ions. s. The genera generall model model is valu valuab able le in that that it prov provid ides es a univ univer ersa sall mode modell of phenomena and would primarily be of interest to construct struction ion ocial ocials. s. The predic predictiv tivee equati equation on has been been develo developed ped as an agg aggreg regate ate model model for actual actual constru construcction time of a public projects. In this this setti setting ng,, more more spec speci® i®cc mode models ls such such as Eqs. Eqs. (2)±(6) (2)±(6) were were develo developed ped,, which which exhibi exhibited ted a reason reasonabl ablee ®t to the the data data.. Figu Figure ress 2±7 give give a grap graphi hical cal view of how well the charts charts relate relate the actual actual time by projec projectt type type to the planne planned d time. time. Speci® Speci®cc model modelss are preferpreferable able and would be of partic particula ularr interes interestt to constru construcc-
tion managers and practitioner practitionerss rather than selection selection of the general model. The ®tted equations are as follows: 3.1. Housing project Y 59X05 1X6X R
0X853 R2 073 SXEX 104X62
F À value
32X19
2
3.2. Oce and administration building Y 95X4 0X97X R
0X76 R2 0X59 SXEX 99X49
3.3. School projects Y 162X05 0X77X
F À value
45X94
3
A.H. Al-Momani Al-Momani / International International Journal of Project Management Management 18 (2000) 51±59
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Fig. 5. Scatter plot of actual time versus planned time of the school buildings model. R
0X71 R2 0X51 SXEX 99X36
F À value
51X97
4
F À value
68X71
5
3.4. Medical centers Y Y 46X9 1X3X R
0X89 R2 0X79 SXEX 108X4
ofthe ofthe estimat estimated ed equati equations ons are reasona reasonable ble,, giv given en that that 2 the R for Eq. (1) through Eq. (6) are of a acceptable value val ue and the corres correspon pondin ding g F-rati F-ratios os indica indicate te very very good good model model identi identi®ca ®catio tions ns and satisf satisfy y the diagno diagnosti sticc crit criter eria ia.. Thes Thesee equa equatio tions ns can can be used used by engi engine neers ers,, planne planners rs and constr constructi uction on manage managers rs worki working ng in govgovernmental agencies to estimate the actual time for construction before awarding contract.
3.5. Communication Communication facilities facilities
4. Limitation and suggestion for further research
Y Y 85 0X84X
While this study is among the ®rst to provide a full test of cause and determinants of construction delay, it is not without limitations. Several shortcomings in the data can be identi®ed such as the actual cost of constructi struction on and constr construct uction ion experi experienc encee of the contra contracctors. tors. The inclus inclusion ion of the constr construct uction ion experi experienc encee of the contractors as a predictor within the model underlines lines the importa importance nce of this this extensi extension on of the analys analysis is into the internal information of the ®rms. But this factor can be introduced only when the focus of study is moved from the construction industry to the construction ®rms. Such change of focus is not without diculties ties.. The The coll collec ecti tion on of the the comp compan any y spec speci® i®cc data data is
R
0X86 R2 074 SXEX 29X27
F À value
22X73
6
The regression coecients are all signi®cantly dierent from zero and the expected sign and relationship between the variables is linear. Each of the tests conducted proved that, the developed developed equations equations are statistically signi®cant at the 99% level as indicated by the t-values and appear to explain a high per cent of the variab var iabil ility ity and able to predic predictt change changess in the actual actual time. time. Other Other releva relevant nt regress regression ion statis statistic ticss are shown shown below below the estim estimates ates.. Overal Overall, l, the explan explanato atory ry power power
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A.H. Al-Momani Al-Momani / International International Journal of Project Management Management 18 (2000) 51±59
Fig. 6. Scatter plot of actual time versus planned time of the medical centers model.
costly costly compar compared ed with with that that of public publicly ly ava availa ilable ble data. data. However, the quality of future studies concerning company speci®c data and managerial perceptions are largely gely depe depend nden entt on the the natu nature re of the the data data that that is available avai lable for analysis. analysis. The future emphasis emphasis should should be placed on the collection of the appropriate information and this will be the subject of an additional paper. Projectsinvestigated in this study exhibit a delay. In practice, this phenomena is expected to continue unless management actions are taken to control these causes within the planned element of the design and construction tion works. works. Thus Thus good good practic practicee in planni planning, ng, coordi coordi-nation nation,, and the change change of the contro controll proced procedure uress of the public institutions needs to be recognised and the implicati implications ons understood. understood. The model still appears appears tenable, then it may be applied broadly for guidance and for planning further work and will prove bene®cial in future projects.
5. Conclusion Conclusion
Construction delay and overrun is a critical function in construction of public projects. It has been of great interes interestt to constr construct uction ion researc researcher herss but has not been been
well understood in the case of public building projects. A survey survey of 130 projects projects indica indicated ted that that poor poor design design and neglig negligenc encee of the owner, owner, change change orders orders,, weather weather condition, condition, site condition, condition, late delivery, delivery, economic conditions, and increase in quantities are the main causes of delay. In line with the reviewed research, the present investi investigat gation ion provid provides es con®rm con®rmati ation on of the eect eect of de®ned parameters parameters on constructio construction n delays. delays. Practically oriented research is vital for proper management agement of constructio construction n projects. projects. Reliable Reliable prediction prediction of constr construct uction ion durati duration, on, and then then contro controlli lling ng cost cost within budget is widely used in decision making and is an essent essential ial part part of succes successfu sfull manag manageme ement. nt. To test test this hypothesis, a simple linear model was used to estimate the relationship between the actual and planned time. The major implication of the foregoing have important rami®cations for understanding the actual time of public projects. This has been repeatedly stated to the outsta outstandi nding ng need need of constru constructi ction on in Jordan Jordan.. The relations obtained have the advantage of relying upon the statistical treatment of real data and could without doubt be improved by considering a larger sample of projec projects. ts. The resear researche cherr believ believes es that that the arg argume uments nts and ®ndings ®ndings presen presented ted in this this study study provid providee a good good guidan guidance ce for manage manageria riall interv intervent ention ion,, and provid providee
A.H. Al-Momani Al-Momani / International International Journal of Project Management Management 18 (2000) 51±59
59
Fig. 7. Scatter plot of actual time versus planned time of the communication facilities model.
some guidelines and actionable information that managers can utilize to manage their projects.
struct struction ion projec projects ts in develo developi ping ng countr countries ies.. CIB CIB Proc, Proc, W-65 W-65 1984;2:273±734. [11] Fereig Fereig S, Qaddumi Qaddumi N. Construc Construction tion problem problemsÐAra sÐArabian bian Gulf Gulf experience. CIB Proc, W-65 1984;2:753±6.
References [1] Hancher Hancher DE, Rowings Rowings JE. Setting Setting highway highway constructio construction n contract tract duration duration.. Journal Journal of the Construc Construction tion Divisio Division, n, ASCE 1981;107(2):169±79. [2] [2] Barr Barrie ie DS, DS, Paul Paulso son n BC. BC. Prof Profes essi sion ona al Cons Constr truc ucti tion on Management. Management. Berkshire, Berkshire, England: McGraw-Hill, McGraw-Hill, 1992. [3] Halpin DW, Woodhead RW. Construction Management. Management. New York: John Wiley, 1980. [4] Harries Harries F, McCaer McCaer R. Modern Modern Construc Construction tion Managem Management. ent. London, England: Blackwell Science, 1995. [5] [5] Oxle Oxley y R, Posk Poskit it J. Mana Manage geme ment nt Tech Techni niqu ques es Appl Applie ied d to Construction Industry. London: Blackwell Science, 1996. [6] Filcher Filcher R. Principl Principles es of Construc Construction tion Managem Management. ent. Berkshir Berkshire, e, England: McGraw-Hill, 1992. [7] Al-Moma Al-Momani ni A. Constru Construction ction cost predicti prediction on for public public school school building in Jordan. Construction Management Management and Economics 1996;14:311±7. [8] Assa Assaff SA, Alkhalil Alkhalil M, Al-Hazm Al-Hazmii M. Causes of delay delay in large buildi building ng const construc ructio tion n projec projects. ts. Journ Journal al of Manag Managem emen entt in Engineering, Engineering, ASCE 1995;11(2):45±50 1995;11(2):45±50.. [9] Wils Wilson on RL. Preventi Prevention on and resoluti resolution on of construc construction tion claims. claims. Journal of Construction Construction Division Division 1982;108(CO3):390± 1982;108(CO3):390±405. 405. [10] Chalabi Chalabi FA, Camp D. Causes Causes of delay delay and overruns overruns of con-
Dr. Ayman H. Al-Momani is an associate profe professo ssorr of civil civil engin enginee eerin ring g at Mu'tah Mu'tah Univers University, ity, Jordan. He is also vice dean of engineer engineering ing and head of chemical chemical enginee engineering ring departme department. nt. He served as a chairman and head of the civil civil engineer engineering ing departme department nt for many many years, and he is in charge of the construction engineering and management management program, where he contributed to and develo developed ped postgr postgrad aduat uatee and underundergraduate courses in construction construction management. He has written widely in the ®eld ®eld and and taug taught ht cour course sess at Mu't Mu'tah ah University, University, University of Jordan, and University University of Applied sciences in construction construction planning and scheduling, construction cost estimating, estimating, constructi construction on manageme management, nt, constructi construction on methods methods and equipmen equipment, t, quality control in construction, construction, engineering economy and operation resea research rch.. He receiv received ed a BS in civil civil engine engineeri ering ng from from Lening Leningra rad d universi university, ty, MS in construc construction tion managem management ent from Oklahoma Oklahoma UniUniversity, MS in industrial engineering from Central State University, and a Ph.D. from Oklahoma State University, USA. He is a member of national and international associations.
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