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Contributors to construction delays.

Kumaraswamy, Mohan M.

Chan, Daniel W. M.

Construction Management & Economics; Jan1998, Vol. 16 Issue 1, p17-29, 13p, 1

Diagram, 14 Charts, 1 Graph

Article

*CONSTRUCTION industry

*PROJECT management

*INDUSTRIAL engineering

*INDUSTRIAL productivity

*QUESTIONNAIRES

HONG Kong (China)

CHINA

delay

Hong Kong

Hong Kong.

PRODUCTIVITY

project management

time

Projects can be delayed for a large number of reasons. The third phase of an

investigation into such factors focused on the causes of construction delays in

Hong Kong. A questionnaire was based on 83 factors identified in previous phases

1

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of the investigation. Analysis of the responses reveals differences in perceptions

of the relative significance of factors between clients, consultants and contractors.

There was general agreement about the relative importance of delay factors such

as unforeseen ground conditions. Improving productivity is a useful approach to

controlling delays. Important factors affecting productivity itself are thus examined

in more depth, with a view to enhancing productivity and reducing delays. The

conclusions of this phase of the investigation include a ranking of factors and

factor categories that are perceived by different groups of project participants to

contribute to delays. For example, higher-ranking factors, such as unforeseen

ground conditions, and factor categories such as project-related factors, are found

to merit special management attention in countering construction delays. The high

degree of disagreement as discerned between the groups of clients, consultants

and contractors is indicative of their experiences, possible prejudices and lack of

effective communication. It is also confirmed that productivity and other non-scope

factors such as effective communications should supplement the project scope

factors incorporated into the construction time prediction models that were

proposed in the previous phases of this investigation. [ABSTRACT FROM

AUTHOR]

Copyright of Construction Management & Economics is the property of Routledge

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applies to all Abstracts.)

Department of Civil and Structural Engineering, The University of Hong Kong,

Pokfulam Road, Hong Kong.

6285

0144-6193

10.1080/014461998372556

253021

Business Source Premier

1

CONTRIBUTORS TO CONSTRUCTION DELAYS

Received 26 October 1995; accepted 8 July 1996

Projects can be delayed for a large number of reasons. The third phase of an investigation into such

factors focused on the causes of construction delays in Hong Kong. A questionnaire was based on 83

factors identified in previous phases of the investigation. Analysis of the responses reveals differences

in perceptions of the relative significance of factors between clients, consultants and contractors.

There was general agreement about the relative importance of delay factors such as unforeseen

ground conditions. Improving productivity is a useful approach to controlling delays. Important factors

affecting productivity itself are thus examined in more depth, with a view to enhancing productivity and

reducing delays. The conclusions of this phase of the investigation include a ranking of factors and

factor categories that are perceived by different groups of project participants to contribute to delays.

For example, higher-ranking factors, such as unforeseen ground conditions, and factor categories

such as project-related factors, are found to merit special management attention in countering

construction delays. The high degree of disagreement as discerned between the groups of clients,

consultants and contractors is indicative of their experiences, possible prejudices and lack of effective

communication. It is also confirmed that productivity and other non-scope factors such as effective

communications should supplement the project scope factors incorporated into the construction time

prediction models that were proposed in the previous phases of this investigation.

Keywords: productivity, project management, delay, time, Hong Kong

Background and introduction

The first two phases of an ongoing investigation into factors affecting construction durations in Hong

Kong (Chan and Kumaraswamy, 1995) focused on project scope variables such as project cost, floor

area and number of floors in buildings. The results were similar to those previously derived by

Bromilow et al. (1988) in Australia and Kaka and Price (1991) in the UK, in respect of the types of

relationship and the correlation between project time and cost. The previous investigation also

indicated the probable impact on construction durations of non-scope factors such as external and

management variables, in line with the conclusions from a recent study in Australia (Walker, 1995a).

Previous reports on the ongoing study into construction time performance in Hong Kong noted that: (a)

productivity was a key factor needing further study (Kumaraswamy and Chan, 1995); and (b) site

organization variables also merited further investigation, in relation to project durations (Chan and

Kumaraswamy, 1995). Furthermore, the second phase of the Hong Kong investigation also

incorporated a case study on construction plant and labour productivity. This indicated the contribution

of productivity levels to activity times, overall construction project durations and construction delays,

for example through different utilization/idling patterns.

This paper highlights the principal findings of the third phase of the Hong Kong investigation, in respect

of the main factors causing delays, as perceived by different industry subsectors: clients, consultants

and contractors. The degree of agreement/disagreement between the subsectors as to the

importance of these factors is also indicated, to illustrate differences in collective perspectives and

any possible popular misconceptions or prejudices. The resulting sectoral and combined rankings of

the main causes of construction delays suggest suitable priorities in devising and focusing strategies

to counteract such critical contributors to delays in future projects.

In developing such counter-delay strategies, a focus on productivity is justified by the main findings of

the questionnaire and literature surveys, both of which indicate a general perception of the significance

of 'non-scope' factors that either directly or indirectly affect productivity levels and project durations.

Lower productivity than planned is thus identified as a key contributor to (or a root cause of) delays,

which therefore merits special attention.

The findings of this phase of the investigation are framed within the context of relevant results of

recent research into construction productivity and other factors affecting construction durations and

construction delays in other countries, in order to consider the general applicability of the conclusions.

Productivity, project durations and delays

Because productivity levels were found to be a principal determinant of project durations (Chan and

Kumaraswamy, 1995), lowered productivity could feasibly contribute significantly to project delays.

The potential for improvement is reflected in the finding that 'productivity rates in the United Kingdom

varied between one site and another by as much as three to one' (NEDO, 1989). Enhanced

productivity is evidently a necessary but not sufficient condition for reducing project durations. While

the productivity of each type of resource (factor), such as labour, may be increased, by motivation for

example, the overall (total factor) productivity will not be correspondingly enhanced unless a proper

balance and appropriate synergy is achieved. This requires effective management of the resources

and their interactions within the project, as well as their interactions with the external environment.

Conversely, project durations have been reduced in practice, despite lower productivity levels, for

example by mobilizing more resources. Seemingly impossible target dates have been achieved by

such deployment of additional resources and/or a sudden surge of synergistic 'partnering' type

teamwork by all project participants who needed to meet a critical deadline. Similarly, project delays

have also been caused by factors other than lowered productivity levels.

For the purposes of the third phase of this investigation, potential delay factors were identified from a

literature review and the observations from the first two phases of the investigation. These were

classified into eight factor categories as follows:

project-related;

client-related;

design team-related;

contractor-related;

materials-related;

labour-related;

plant/equipment-related;

external factors.

Although a certain degree of overlap may be anticipated between these categories, this was

minimized during the specific allocations of the 83 factors. It was noted that: (a) there may be

interactions between the factor categories, for example in one affecting the other either positively or

negatively; and (b) achieved (vs planned) productivity levels can affect many of the categories (as a

common root cause), for example in design team productivity, contractors' organizational productivity,

labour productivity and plant productivity.

Projects can be delayed by the impact of such factor categories; it was also noted that these may

interact to produce 'multiplier' effects, where problems in one category may trigger further problems in

another. For example, weak contractor management may lower labour morale, and decrease plant

productivity as well.

Survey methodology

The survey questionnaire was designed on the basis of 83 previously identified delay-causing factors

divided into the foregoing eight factor categories. Respondents were requested to rate the significance

of each factor as either extremely significant, very significant, moderately significant, slightly significant

or not significant. The first page of the five-page questionnaire is reproduced in Appendix 1.

This questionnaire was sent to 400 clients, consultants and contractors in Hong Kong in December

1994, requesting responses based on projects completed between 1990 and 1994. Follow-up

communications led to the return of 147 completed questionnaires. The distribution of the

respondents, as classified according to their industry grouping (clients, consultants or contractors)

and their main works type (buildings or civil engineering) is indicated in Appendix 2.

The profile of the respondents in terms of their average work experience in each such group, as

indicated in Appendix 3, confirms the considerable experience on which the responses are based. It is

noted that the subjective and general nature of the responses required would be less reliable than

more quantifiable information, or that obtained from specific projects. However, it must be also noted

that this survey supplements (and is supplemented by) a previous survey, which derived such

quantifiable data from specific projects (Chan and Kumaraswamy, 1995), but which also indicated the

need for wider experience-based assessments of factors causing delays. The questionnaire survey

was supplemented by follow-up interviews to clarify some of the responses.

Survey findings Observations and analysis

Table 1 presents a profile of the magnitudes of time overruns, as observed on different types of

projects during the first survey in 1993/94. This profile indicates that project delays are fairly common

in Hong Kong.

Tables 2 and 3 summarize the responses in respect of the 20 most important factors causing delays

as perceived by two of the six groups surveyed: contractors on building projects and consultants on

civil engineering projects, respectively. Four more of such summarized response sheets were

obtained for the other groups surveyed, but are not reproduced here, to save space. However, the

consolidated summaries that are presented later (in Tables 4, 5 and 8) reflect the comparative results

from the other groups as well.

The relative importance index (RII) derived to summarize the importance of each 'factor' was

computed as

Multiple line equation(s) cannot be converted to ASCII text

where: w = weighting as assigned by each respondent in a range from 1 to 5, where 1 implies 'not

significant' and 5 implies 'extremely significant'; A = the highest weight (5); N = the total number in the

sample.

The relative rankings of the factors within each group from 1 to 20 are also indicated in Tables 2 and 3.

These were assigned on the basis of the factor RIIs. Where the RIIs were the same for two or more

factors, rank differentiation was achieved by examining the distribution of the ratings against such

factors. For example, if more respondents had ranked one of the factors as either 'extremely

significant' or 'very significant' (i.e. more ranks of 4 or 5, than assigned to another factor), then the

former was assigned the higher rank.

The next step distinguished between building works and civil engineering works, thereby dividing each

of the three participant groups into two such work types, with each work type containing the three

groups of clients, consultants and contractors. The weighted average of the RIIs for each of the

previously selected 20 factors from each group was next computed within each work type, by

combining it with the RIIs from the other two groups. This combination of three RIIs to find the

weighted average for each factor within each work type was achieved by adding the products of (a)

the RII for each group and (b) the proportion of respondents from the corresponding group (as a

proportion of the total respondents, as can be derived from Appendix 2). For example, the weighted

average of the factor 'poor site management and supervision' in the 'building works' type, as in Table

4, was computed as 0.800 x (27/78) + 0.858 x (24/78) + 0.822 x (27/78) = 0.825, as appears in Table

4.

The ten factors with the highest weighted averages in the 'buildings works' and 'civil engineering

works' types are shown in Tables 4 and 5 respectively. Figures 1 and 2 facilitate a visual comparison

of the RIIs, (as derived from the perceptions of the different groups) of the ten most significant factors

in respect of the 'building works' and 'civil engineering works' types respectively.

The overall RIIs for each of the eight factor categories were next determined for each group in turn, by

taking the mean of all factor RIIs in that category. The weighted averages of these overall RIIs from the

factor categories were obtained for three building works groups as in Table 6; and for the three civil

engineering works groups as in Table 7.

The rank agreement factors (RAFs) were next computed using the formula and methodology

described by Okpala and Aniekwu (1988) to measure the agreement in ranking between groups of

project participants. The RAF can range from 0, indicating perfect agreement, to higher values

indicating increasing disagreement. The percentage disagreement and the percentage agreement

(PA) were computed from the RAF, also using the prescribed formulae.

Table 8 records the RAFs and PAs as computed for the ten most significant factors causing delays,

as perceived by the different groups. Table 9 records the RAFs and PAs in respect of the relative

importance of the eight factor categories themselves, as perceived by the different groups. A further

overall comparison between the building works and civil engineering works as a whole yields a RAF of

0.50 and a PA of 87.5%, indicating a high overall correlation. Figure 3 illustrates the proportions of

agreement between the different groups based on the PAs in Tables 8 and 9.

Specific conclusions from the survey

While the detailed results as indicated in Tables 2-9 and Figures 1-3 contain a wealth of information,

the following specific conclusions are relevant to the focus of this paper.

There is a fair degree of agreement between the groups in their ranking of the factor categories,

particularly between clients and consultants. However, there is an apparent divergence in perceptions

between clients and contractors, or even between consultants and contractors, on many specific

factors themselves: this is reflected in the percentage agreements (PAs) in Tables 8 and 9 and Figure

3.

For example, the clients and consultants appear to agree on the significance of the contractor-related

factor category in contributing to delays in both building works and civil engineering works, as per

Tables 6 and 7. However, an examination of the significant 'factors' so identified does not appear to

reflect this general perception to a corresponding extent in the case of the specific factors in Tables 4

and 5. This apparent anomaly could perhaps be explained, for example, as a general 'conditioning' of

one group (such as consultants) vis-a-vis another (such as contractors), which may manifest itself in

a random distribution of adverse responses relating to the latter group in general, i.e. within the

relevant factor category, despite a lack of agreement on specific factors.

The top ten significant factors as isolated separately for building works and civil engineering works, as

identified in Tables 4 and 5 respectively, yield six common factors, as listed in Table 10.

Of the remaining four significant factors from building works, two are contractor related, one is project

related, and the other is design-team related. On the other hand, three of the four remaining factors

from civil engineering works are contractor related, with the other -classified as labour related - also

usually being within the purview of the contractor.

It is evident that there are differences in the perceptions of different groups as to the causes of

construction delays. Such perceptions may be attributed to a certain degree of group bias, arising

either from some specific experiences, from limited exposure, and/or from conditioning by colleagues.

Even though the recorded experience levels of the survey respondents seem sufficiently high, and not

dissimilar between groups as in Appendix 3, some bias is evident in the group perceptions. Perhaps

the wording of the factors and the classification of the factor categories in the questionnaire itself may

also be re-examined to minimize any defensive posturing or 'buck passing' by different groups; but a

residual bias is apparent even if allowances are made for this possible distortion.

Unfortunately, such biases may be counterproductive: for example, when blaming other groups, rather

than examining the real causes of delays. Such differences of perception and their consequences can

also lead to claims for extension of time that generate further pressures to direct or deflect blame,

rather than seek root causes and solutions.

A re-examination of Tables 6 and 7 relating to significant factor categories indicates that project-

related factor categories rank only fifth in significance, whereas contractor-related, design-team-

related and labour-related factor categories rank first, second and third respectively. This suggests

that project- (or scope-) related factors are not that significant in the context of delays (although they

are important in establishing the project durations at the outset), in comparison with the

aforementioned first three factor categories, and even the fourth (external conditions). Furthermore,

case studies and interviews during this investigation indicated the importance of productivity levels of

the contractor, of the design team, and of the labour itself, in contributing to the significance of the first

three (as ranked) aforementioned factor categories. It was also noted that the wide variations possible

in such productivity levels could well contribute to project delays (Chan and Kumaraswamy, 1995).

The foregoing conclusion re-confirms previous findings, from this investigation and from the literature,

as to the significance of productivity in determining project durations and in contributing to delays. This

also suggests a re-examination of methods of measuring and improving productivity levels in

construction projects, as one important approach to avoiding or minimizing delays.

A re-examination of aspects of construction productivity that contribute to project delays

Concept and classifications

Commencing with the basic conceptualization of productivity as output/input, Prokopenko (1987)

identified three main productivity factor groups as:

job related;

resource related;

environment related.

He also distinguished between (a) external (non-controllable) and (b) internal (controllable) factors,

further subdividing the latter into hard factors (those related to product, plant and equipment,

technology, materials and energy) and soft factors (people, organization and systems, work methods

and management styles).

The importance of total factor productivity as against single factor productivity -- to construction

organizations and to the industry itself -- has been reported previously (Ganesan, 1984). The former

takes into account all input resources (factors), whereas the latter is usually useful only in the case of

a critical or scarce resource, such as skilled labour.

Improving productivity levels

The observations from the Hong Kong survey in the current investigation indicated the perceived

importance of contractor-related, design-team-related and labour-related factor categories. This

appears to: (a) align with the concept of increasing total factor productivity and of synergizing the

inputs to optimize the outputs; and (b) provide a reminder of the importance of organizational variables

in both contractors and design organizations. For example, the rapid response and constructive inputs

of design teams to site problems enhance productivity and reduce delays.

Special work study techniques such as multiple-activity charts and activity sampling have been

adapted and developed for measuring and improving construction productivity (Heap, 1987; McCaffer

and Harris, 1995), but there is little evidence as yet of their popular usage in the industry, for example

in structured and scientific approaches to developing improved work methods and in establishing and

improving work norms. Such techniques and tools can be useful to organizations with a longer-term

perspective: i.e. those prepared to invest in improved productivity despite short-term pressures or

priorities. Their usefulness is underlined by the significantly variable construction productivity levels

indicated by the literature (NEDO, 1989); and by the previous (second) phase of this investigation

(Chan and Kumaraswamy, 1995), which indicated potential improvements through better plant and

labour utilization and appropriate methodologies, for example in concreting.

Factors affecting productivity and project durations

Lim and Price (1995) cited (a) the following seven factors identified as affecting overall construction

productivity in Singapore:

buildability;

structure of the industry;

training;

mechanization and automation;

foreign labour;

standardization;

building controls.

and (b) the following ten factors identified as affecting labour productivity:

quality, number and balance of labour force;

motivation of labour force;

degree of mechanization;

continuity of work as affected by supply of materials, performance of other contractors or

subcontractors, availability and adequacy of technical information, and variations;

complexity of project;

required quality of finished work;

method of construction;

type of contract;

quality and number of managers;

weather.

The apparent complexity is magnified when considering: (a) the possibilities of interactions between

such factors affecting labour productivity, and (b) the fact that similarly complex networks of factors

may simultaneously affect other factor productivities, such as that of equipment. The consequential

impacts on project activities could well lead to project delays.

It is thus necessary to focus on critical factors affecting overall (or total factor) productivity. Maloney

(1983) confirmed that labour has a significant influence on construction productivity, and that

management in turn has a major impact on labour productivity. He identified sets of specific driving,

induced and restraining forces acting positively and negatively on productivity levels, and formulated

approaches based on such forces to facilitate productivity improvements.

Motivation of both management and labour can be hypothesized as a key contributor to productivity.

Methods of motivating personnel to increase productivity have been demonstrated by Khan (1993),

through applications of different human relations theories of motivation. Such enhancement of

productivity could help to counteract delays induced by other causes. Conversely, a lack of proper

management can, even 'by default', mobilize factors that adversely affect productivity and lead to

project delays.

Other factors affecting construction time performance

The literature review of recent research also revealed many factors that were found to affect

construction time performance, apart from those factors that achieved such effects through their initial

impact on productivity levels.

For example, Nkado (1995) demonstrated the prioritization of construction-time-influencing factors that

can be incorporated in an information system, which could then help in planning project durations. He

used 12 scope-related variables, such as gross floor area, to develop this particular model, but had

also previously examined a total of 33 time-influencing factors that had been identified from the

literature. From the latter, he identified the ten most important factors, including for example client and

designer's priority on construction time. He also identified the ten least important factors from this set

of 33, including for example the form of contract and its suitability for the project.

In a similar context, an investigation of the relationship between the building team, procurement

method and project performance by Naoum and Mustapha (1995) did not yield enough evidence to

confirm the claim that alternative procurement methods shorten construction times. Parallels can thus

be drawn with the work of Walker (1995b) in Australia, which 'revealed that contract type does not

affect the speed of construction', and that several client-related factors proved more significant,

particularly as to 'how well the clients or their representatives relate to the project team'. Walker

(1995a) also found that the 'four factors affect(ing) construction time performances and best practice

worldwide were:

construction management effectiveness;

the sophistication of the client and the client's representative in terms of creating and maintaining

positive project team relationships with the construction management and design team;

design team effectiveness in communicating with construction management and client's

representative teams;

a small number of factors describing project scope and complexity.

Such findings collaborate the results of the questionnaire survey in Hong Kong, as to the relative

significance of non-scope factor categories, such as 'contractor related', 'design team related' and

'labour related' in contributing the construction delays. Specific factors also highlighted as significant in

this study included poor site management and supervision, low speed of decision making involving all

project teams, delays in design information, and lack of communication between consultant and

contractor.

Concluding observations

The third phase of this investigation into factors affecting construction durations led to the identification

of some major causes of construction project delays. Both the questionnaire survey results in Hong

Kong and the review of recent relevant research revealed the significance of non-scope contributors

such as project participant priorities and relationships. Such contributors affect project durations both

directly, and indirectly through their effects on productivity levels.

For example, the questionnaire survey indicated the perceived importance of the impact on

construction delays of the contractor-related, design-team-related and labour-related factor

categories. The particular contribution of variable productivity levels to these significant factor

categories was noted, leading to an examination of factors affecting productivity itself and of how

productivity could be considerably enhanced and delays minimized, through techniques such as work

study. Another aspect of consistently increased productivity levels, although not explored in this paper,

is the possibility of reductions in the planned project durations themselves, in the first instance. An

integration of these findings with those from the previous phases of the ongoing study (Chan and

Kumaraswamy, 1995) confirms that productivity is one of the key factors in determining both planned

and achieved project durations, and that while project scope factors must be used to model the

planned project durations, other non-scope factors need to be incorporated in the model, in setting the

baselines and in adjusting for particular priorities, capabilities and motivations of the interacting project

participants.

The questionnaire survey in this investigation also revealed differences in perceptions as to causes of

delays by different groups of project participants: clients, consultants and contractors in building works

as well as in civil engineering works. It is suggested that these apparent collective biases of different

industry groups may often direct blame for delays to other groups, and discourage a search for the

root causes of delays and solutions to same. The origin of such biases may be traced to group

conditioning, as well as to the present adversarial nature of the contractual systems, including the

clashes, blame allocation and defensive postures induced by the not uncommon 'extension of time'

claims and associated costs in construction contracts.

Studies on causes of project delays must thus make allowances for such biases when verifying the

real reasons, whether through interviews or through selected project documents. Furthermore, special

efforts must be made to overcome such biases, as well as to analyse and address the factors and

factor categories identified in this study and the literature, as significant contributors to project delays.

Particular strategies may be designed to address the significant factors, such as unforeseen ground

conditions, poor site management and supervision, and delays in design information. As a general

principle, for example, more intensive site investigations and stronger management are probably

warranted in projects where delays can be crucial. Of course, such principles need to be translated

into practice through appropriate guidelines and project-specific procedures.

This study thus provides pointers to appropriate strategies and particular measures that may be

adopted to avoid and/or mitigate project delays by focusing on the direct and indirect common

contributors to same, such as delays in design information and productivity levels. While the present

survey was based in Hong Kong, the international literature revealed general similarities that may merit

detailed comparative investigations elsewhere.

Table 1 Percentage of time overruns in the three project samples in the previous survey in Hong Kong

Legend for Chart:

A - Actual percentage of time overrun

B - Government building projects (%)

C - Private building projects (%)

D - Civil engineering projects (%)

A B C D

0 40 25 34

1-10 27 28 21

11-20 11 17 21

21-30 14 11 13

31-40 5 1 15

41-50 3 0 3

>50 0 8 3

Mean percentage of time overrun 9 17 14

Sample size 37 36 38

Table 2 Contractors' responses and ranking of the significance of factors causing delays in building

projects (sample size = 27)

Legend for Chart:

A - Hypothesized factors (1)

B - Percentage of respondents scoring: >/=4 (2)

C - Percentage of respondents scoring: 3 (3)

D - </=2 (4)

E - Relative importance index (5)

F - Rank (6)

A B C

D E

F

Delays in design information 88.89 7.41

3.70 0.889

1

Long waiting time for approval

of drawings 85.19 11.11

3.70 0.822

2

Poor site management and supervision 81.48 14.82

3.70 0.822

3

Unrealistic contract durations

imposed by client 75.00 25.00

0.00 0.817

4

Mistakes and discrepancies

in design documents 81.48 14.82

3.70 0.815

5

Long waiting time for approval

of test samples of materials 77.78 18.52

3.70 0.815

6

Inappropriate overall

organizational structure

linking all project teams 66.67 29.63

3.70 0.807

7

Inadequate design team experience 81.48 11.11

7.41 0.8

8

Lack of communication between

consultant and contractor 74.07 22.23

3.70 0.8

9

Low speed of decision making

involving all project teams 74.07 14.82

11.11 0.8

10

Delays in subcontractors' work 69.23 26.92

3.85 0.792

11

Inadequate contractor experience 62.96 33.34

3.70 0.785

12

Necessary variations 74.07 22.23

3.70 0.778

13

Disputes/conflicts 77.78 14.81

7.41 0.770

14


within each project team 70.37 22.22

7.41 0.770

15


client and consultant 66.67 22.22

11.11 0.770

16

Shortage of materials in markets 62.96 25.93

11.11 0.770

17

Client-initiated variations 74.07 22.23

3.70 0.763

18

Unforeseen ground conditions 66.67 25.92

7.41 0.756

19

Slow information flow between

project team members 62.96 37.04

0.00 0.756

20

Table 3 Consultants' responses and ranking of the significance of factors causing delays in civil

engineering projects (sample size = 25)

Legend for Chart:

A - Hypothesized factors (1)

B - Percentage of respondents scoring: >/=4 (2)

C - Percentage of respondents scoring: 3 (3)

D - </=2 (4)

E - Relative importance index (5)

F - Rank (6)

A B C

D E

F

Unforeseen ground conditions 80.00 12.00

8.00 0.816

1

Inadequate contractor experience 80.00 16.00

4.00 0.8

2

Poor site management and supervision 68.00 28.00

4.00 0.792

3

Inappropriate type of foundations 78.26 13.04

8.70 0.791

4


involving all project teams 75.00 12.50

12.50 0.783

5

Necessary variations 72.00 24.00

4.00 0.776

6

Client-initiated variations 76.00 16.00

8.00 0.768

7

Deficiencies in planning and scheduling

at preconstruction stage 72.00 12.00

16.00 0.76

8

Unsuitable leadership style of

contractor's construction manager 68.00 20.00

12.00 0.76

9

Improper control over site

resource allocation 56.00 36.00

8.00 0.76

10

Slow information flow between

project team members 70.83 16.67

12.50 0.758

11

Shortage of plant/equipment 68.00 20.00

12.00 0.752

12

Unsuitable management structure

and style 68.00 20.00

12.00 0.752

13

Low speed of decision making within

each project team 62.50 33.33

4.17 0.75

14

Inadequate managerial skills 64.00 28.00

8.00 0.736

15

Shortage of skilled labour 60.00 32.00

8.00 0.736

16

Inappropriate type of main construction 70.83 20.83

8.34 0.733

17

Small extent of design information

available at construction start 66.66 16.67

16.67 0.733

18

Shortage of managerial and supervisory

personnel 72.00 12.00

16.00 0.728

19

Delays in subcontractors' work 60.00 32.00

8.00 0.728

20

Table 4 Relative importance indices (RII) of the ten most significant factors causing delays in building

works (in descending order of significance)

Legend for Chart:

A - Hypothesized factor

B - Factor category

C - Clients (RII)

D - Consultants (RII)

E - Contractors (RII)

F - Weighted average

A

B C D

E F

Poor site management and supervision related

Contractor 0.800 0.858

0.822 0.825

Unforeseen ground conditions

Project related 0.763 0.842

0.756 0.814

Delays in design information

Design team related 0.689 0.742

0.889 0.775


consultant and contractor


0.8 0.774

Inadequate contractor experience

Contractor related 0.763 0.765

0.785 0.771


involving all project teams


0.800 0.761

Client-initiated variations

Client related 0.741 0.808

0.763 0.757

Necessary variations of works


0.778 0.756

Delays in subcontractors's work


0.792 0.755

Improper control over site

resource allocation


0.719 0.754

Table 5 Relative importance indices (RII) of the ten most significant factors causing delays in civil

engineering works (in descending order of significance)

Legend for Chart:

A - Hypothesized factor

B - Factor category

C - Clients (RII)

D - Consultants (RII)

E - Contractors (RII)

F - Weighted average

A

B C D

E F

Unforeseen ground conditions


0.8 0.814

Poor site management and supervision


0.710 0.796




0.743 0.761

Client-initiated variations

Client related 0.757 0.768

0.743 0.757

Necessary variations of works


0.733 0.756

Inadequate contractor experience


0.632 0.755

Unsuitable management structure

and style of contractor


0.7 0.743

Contractor's deficiencies in planning

and scheduling at preconstruction stage


0.648 0.739

Shortage of managerial and supervisory

personnel


0.695 0.730

Unsuitable leadership style of

contractor's construction manager


0.67 0.730

Table 6 Relative importance indices (RII) and ranks (R) for different factor categories, and by different

survey respondents in the building works grouping

Legend for Chart:

A - Factor category

B - Client: RII

C - Client: R

D - Consultant: RII

E - Consultant: R

F - Contractor: RII

G - Contractor: R

H - Weighted average: RII

I - Weighted average: R

A B C D

E F G

H I

Project related 0.588 6 0.645

4 0.672 5

0.635 5

Client related 0.572 8 0.609

7 0.649 7

0.610 8

Design team related 0.641 3 0.677

3 0.778 1

0.700 2

Contractor related 0.708 2 0.711

1 0.699 3

0.706 1

Materials 0.606 4 0.600

8 0.681 4

0.630 6

Labour 0.717 1 0.682

2 0.662 6

0.687 3

Plant/equipment 0.577 7 0.636

5 0.634 8

0.615 7

External 0.598 5 0.632

6 0.746 2

0.660 4

Table 7 Relative importance indices (RII) and ranks (R) for different factor categories, and by different

survey respondents in the civil engineering grouping

Legend for Chart:

A - Factor category

B - Client: RII

C - Client: R

D - Consultant: RII

E - Consultant: R

F - Contractor: RII

G - Contractor: R

H - Weighted average: RII

I - Weighted average: R

A B C D

E F G

H I

Project related 0.619 4 0.646

4 0.615 5

0.628 5

Client related 0.526 7 0.610

7 0.571 7

0.570 7

Design team related 0.639 3 0.681

2 0.677 1

0.666 2

Contractor related 0.701 1 0.701

1 0.632 4

0.680 1

Materials 0.520 8 0.591

8 0.555 8

0.556 8

Labour 0.665 2 0.680

3 0.643 3

0.665 3

Plant/equipment 0.604 6 0.645

5 0.574 6

0.610 6

External 0.605 5 0.618

6 0.672 2

0.630 4

Table 8 Cross-comparison of the relative importance of the ten most significant factors causing

delays as perceiver by the different groups of respondents

Legend for Chart:

A - Project participant

B - Rank agreement factor: Building

C - Rank agreement factor: Civil

D - Percentage agreement: Building

E - Percentage agreement: Civil

A B C D E

Clients and consultants 2.0 2.6 60 48

Consultants and contractors 3.4 2.4 32 52

Clients and contractors 4.2 3.6 16 28

Table 9 Cross-comparison of the relative importance of factor categories causing delays as

perceived by the different groups of respondents

Legend for Chart:

A - Project participant

B - Rank agreement factor: Building

C - Rank agreement factor: Civil

D - Percentage agreement: Building

E - Percentage agreement: Civil

A B C D E

Clients and consultants 1.50 0.50 62.5 87.5

Consultants and contractors 2.50 1.25 37.5 68.75

Clients and contractors 1.75 1.25 56.25 68.75

Table 10 The six common significant factors from both building works and civil engineering works

Factor Factor category

Unforeseen ground conditions Project related

Poor site management and Contractor related

supervision

Low speed of decision making Project related


Client-initiated variations Client related

Necessary variations of works Project related

Inadequate contractor experience Contractor related

GRAPH: Figure 1 Comparison of the relative importance indices (RIIs) of the factors considered most

significant by clients, consultants and contractors of building works (as in Table 4): 1. poor site

management and supervision; 2. unforeseen ground conditions; 3. delays in design information; 4.

lack of communication between consultant and contractor; 5. inadequate contractor experience; 6.

Low speed of decision making involving all project teams; 7. client-initiated variations; 8. necessary

variations of works; 9. delays in subcontractors' work; 10. improper control over site resource

allocation

GRAPH: Figure 2 Comparison of the relative importance indices (RIIs) of the factors considered most

significant by clients, consultants and contractors of civil engineering works (as in Table 5): 1.

unforeseen ground conditions; 2. poor site management and supervision; 3. low speed of decision

making involving all project teams; 4. client-initiated variations; 5. necessary variations of works; 6.

inadequate contractor experience; 7. unsuitable management structure and style of contractor; 8.

contractor's deficiencies in planning and scheduling at preconstruction stage; 9. shortage of

managerial and supervisory personnel; 10. unsuitable leadership style of contractor's construction

manager

GRAPH: Figure 3 Percentage agreement (PA) between different groups as to (a) factors and (b) factor

categories contributing to project delays; based on Tables 8 and 9 respectively

References

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Appendix 1: First page of five-page questionnaire for research project SECTION A: GENERAL

ORGANIZATION INFORMATION

Date information collected

Name of organization

Major type of work involved (e.g. buildings, roads or others)

Contact person and designation

Relevant working experience year(s)

Contact address

Contact phone No. Contact Fax. No.

SECTION B: FACTORS INCREASING CONSTRUCTION DURATIONS OF PROJECTS

COMPLETED DURING 1990-1994 IN HONG KONG

Please indicate the significance of each factor by ticking the appropriate boxes. Add any remarks

relating to each factor on the last column e.g. as to the reasons, the critical factors or the solutions.

E.S. = extremely significant (100)

M.S. = moderately significant (50)

N.S. = not significant (0)

V.S. = very significant (75)

S.S. = slightly significant (25)

Hypothesized E.S. V.S. M.S. S.S. N.S. Remarks

factors (100) (75) (50) (25) (0)

1. Project-related

factors

Necessary variations

Inappropriate type of

contract used (e.g.

traditional,

design-and-build, etc.)

Type of project

(e.g. building or civil)

End use of product

(e.g. housing, office or

bridge)

Work type (e.g. new,

refurbished, mixed, etc.)

Large gross floor area

of building

Appendix 2: Distribution profile of respondents to the survey questionnaire

Legend for Chart:

A - Project category

B - Clients

C - Consultants

D - Contractors

E - Total

A B C D E

Building works 27 24 27 78

Civil works 23 25 21 69

Total 50 49 48 147

Appendix 3: Work experience profile (in years) of respondents to the survey questionnaire

Legend for Chart:

A - Project category

B - Clients

C - Consultants

D - Contractors

E - Mean

A B C D E

Building works 15.2 15.0 13.2 14.4

Civil works 13.9 17.4 18.8 16.7

~~~~~~~~

By Mohan M. Kumaraswamy and Daniel W. M. Chan

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