Sci., Tech. and Dev., 32 (3): 266-275, 2013

*Author for correspondence E-mail: asamoaho@yahoo.com

ESTIMATING CONTINGENCY SUM FOR BUILDING

WORKS IN GHANA

RICHARD ODURO ASAMOAH1*, JAMES COFIE DANKU

2 AND P.D. BAIDEN AMISSAH

1

1Research Scientist, Building and Road Research Institute, Council for Scientific and Industrial Research,

Kumasi, Ghana. 2Department of Building Technology, Kwame Nkrumah University of Science and Technology, Ghana.

Abstract

It is a common practice in the construction industry in Ghana to allow for contingencies to cater for any unforeseen events. This study was to identify existing methods of determining contingency sum, factors influencing contingency sum and develop a new system of determining contingency sum. The study employed a case study of some 38 completed building projects in Ashanti and Brong Ahafo regions of Ghana to compare the accuracy of both the existing and the new method. Questionnaires were distributed to the selected professionals. Relative Importance Indices Ranking and the Kendall coefficient of concordance were used to rank factors and the agreement of factors ranking among building professions. It was established that the most commonly used method is the Percentage Approach method. The study revealed that 77% of the building professionals have been using the Percentage Approach and 23% have been using the Probabilistic Estimation Methods. These methods were based on subjective approach. Economic, Environmental and Technical factors were identified as the most influential factors. The study concludes by developing a new software system of determining contingency sum and new method was found to be 45% more accurate than the Percentage Approach.

Keywords: Contingency sum, Factors, Existing methods, Proposed new method.

Introduction

Contingency sum has been defined as an additional fund, meant to cater for unforeseeable elements of cost, within the defined project scope. The purpose of contingency sum is to generate a reserve fund that may be sufficient to manage the inherent risk within the project, so as to complete it on time (Ford, 2002). In Ghana, it is characteristics of a construction work to proceed without any risk appraisal. In order to address any future risk, high contingency sums are included in the mark-ups (Badu, 2004). There has been little empirical research into the concept of contingency sum, its intended scope and methods of estimating contingency sum in infrastructure development contracts. The difficulty in determining contingency sum depends on technical, economic and institutional factors (Tawiah, 1999). Inappropriate contingency sums have resulted in poor management of risk leading to underestimation or overestimation, delay in the completion of projects and abandonment of

projects altogether. In particular, overestimated contingency sums limit the cash-flow to contractors. To address these problems, it is important for building professionals to consider other methods of determining contingency sums. Determination of an appropriate contingency sum requires an understanding of how estimators make budget contingency decisions and the impact on the level of accuracy of the included contingency sum. The contingency sum is usually expressed as a percentage mark-up on the base estimate (Picken and Mak, 2001). In the construction industry, building professionals have not been able to state the actual percentage range for Contingency Sum. Available information, however, indicates percentage ranges of 2.5% - 10%, which have been determined for some selected projects financed by the Government of Ghana and other development partners, such as, the African Development Bank and the World Bank from 1999 to 2007 (GPRP/SIF, 2004). The amount for contingency sum varies but 10% is

ESTIMATING CO NTINGENCY SUM FOR BUILDING WORKS IN GHANA 267

recommended for lump sum projects and for other types of contracts (cost plus contracts), it is advisable to set contingency above 10% (Davey, 1992).

Existing Method(s) of Determining Projects

Contingency Sum in Building Works

Baccarini in 2005 came out with 14 methods of determining contingency sum for construction works. The methods are as follows;

Deterministic Estimation (Percentage Addition)

Range Estimating

Analytical Hierarchy Process

Monte Carlo Simulation

Probabilistic Estimating

Methods of Moments

Factors Rating Individual Risks – expected value

Regression

Artificial Neural Networks

Fuzzy Sets

Controlled Interval Memory

Influence Diagrams

Theory of Constraints

Preliminary survey conducted in the study indicated that among the above methods, building professionals had knowledge or had used the following methods before. These methods were:

(i) Deterministic Method (Traditional or Percentage addition estimate).

(ii) Probabilistic Estimation (Based on experience of past projects completed)

(iii) Estimating using Risk Analysis (ERA) (iv) Range Estimating (v) Monte Carlo Simulation

This study therefore used these known methods to determine the most widely used method in the building construction industry in

Ghana. The study showed that the ‘Deterministic Approach’ (Percentage Approach) was the most widely used and known method for determining Contingency Sum by professionals in Ghana. As indicated in Table 2, 77% of the sampled professionals have been using the Deterministic Approach and only 23% have been using the Probabilistic Estimation. The sampled professionals had knowledge about the Estimating using Risk Analysis, Range Estimating and the Monte Carlo methods of determining the Contingency Sum, but have not used any of the methods before.

Methodology and Data Collection

In this study, initial review of documents on the subject was conducted. Data collection was carried out using the stratified random sampling technique. The target population comprised construction professionals, working in Kumasi and Accra. The target professionals were Architects, Civil Engineers and Quantity Surveyors. Furthermore, Kumasi and Greater Accra are the commercial cities in Ghana where many of the working building professionals are located and most of the construction activities in the country could be located. Using the Kish (1965) formula, the overall sample size of 224 was obtained and assuming a return rate of 45%, the sample size was increased to 250. Two hundred and fifty (250) questionnaires were administered to professionals in the building industry. A total of 133 questionnaires representing 53.2% of the total questionnaire administered were returned. The return rate was high for the Quantity Surveyors and out of the 53.2% returned questionnaire as indicated in Table 1. 79.70% were responsive and 20.3% were not responsive.

Table 1. Questionnaire Response from Professionals.

Building Professionals No. of Q uestionnaires Distributed

No. of Q uestionnaires Returned

% Rate of Returned

Quantity Surveyors 90 52 57.8

Architects 80 41 51.3

Civil/Structural

Engineers 80 40 50

Total 250 133 53.2 Source: Field Survey, February – March, 2007

268 RICHARD ODURO ASAMOAH ET AL.

Table 2. Questionnaire Response from Professionals.

Methods Quantity

Surveyors Architects

Civil

Engineers Total %

Percentage Approach

(Existing Method) 43 27 21 91 77

Probabilistic Method 8 12 8 23 23

Range Estimating 0 0 0 0 0

ERA 0 0 0 0 0

Monte Carlo 0 0 0 0 0

Total 51 39 29 119 100

Source: Field Survey, February – March, 2007

Kendall (1970) coefficient of concordance,

the best estimate of true ranking (rating) of ‘n’ objects is provided, where ‘W’ (the coefficient of concordance) is significant by the order of various sums of ranks. If one accepts the criteria used by the judges, then the best true ranking is provided by the mean of the ranks. This implies that most factors influencing contingency sum are the highest overall ranking. Based on the above premise, the overall rankings were calculated for the Quantity Surveyors, Architects and Civil Engineers. The Kendall’s concordance co-efficient, which measures the degree of agreement among professionals of ranking, is expressed as

W = [k

(Ri – Ř) 2] ∕ [n (n2-1)/12]

where,

k = the number of set of ranking (e.g. the number of judgments)

n = the number of aspects of a problem or factors being ranked.

Ř= average of the ranks assigned to the nth

aspect of the problem

n(n2-1)/12 = the maximum possible squared

deviation, i.e., the numerator, which will occur if there were perfect agreements among k sets of ranks, and the average ranking were 1, 2, 3, …, n.

Ri = the rank assigned by an individual judge to one aspect of the problem posed.

The sixth version of the Visual Basic (VB) was used to develop a simple calculator for determining contingency sum as shown in Fig. 2.

The New Method of Determining Contingency

Sum

The study adopted and modified risk rating factors developed by the American Association of Cost Engineers (AACE, 2008), as shown in Table 3, to develop a system for determining contingency figure as a percentage to be added to project cost. The method is a visual basic programme designed to cover identified factors influencing the determination of contingency sum. The factors have been grouped into Economic, Technical and Environmental/Cultural Factors. From the study Technical and Environmental/Cultural Factors contribute 20% respectively to the determination of contingency sum, whiles Economic factors contributes 60%. Each of the main factors has related minor factors. Each of these minor factors has risk rated values, which vary depending on conditions and the impact of risk as identified by the project team, as shown in Table 3 and Fig. 1. Fig. 2 shows the pictorial nature of the Proposed Method.

Table 5 shows the list of projects that were used for the case studies. The projects were under the sponsorship of the government of Ghana and the development partners, including the World Bank, African Development Bank and the Arab Bank. Projects include the following;

Basic Education Support Project (BESP)

Rehabilitation and Upgrading of Second Cycle Schools (Effiduase Senior High School)

Primary Education Rehabilitation Project (PERP)

ESTIMATING CO NTINGENCY SUM FOR BUILDING WORKS IN GHANA 269

Highly Indebted Poor Country / Ghana Education Trust Fund Projects (HIPC/GETFUND)

Promoting Partnership with Traditional Authorities Project (PPTAP).

Table 3. Risk Factor Rating

Item Factors Risk Factors Minimum Medium Maximum

1. Environmental/

Institutional 20%

A Demand for Extractive

Materials 11 0 5 11

B Force Majeure 7 0 4 7

C Cultural Implication 2 0 1 2

2. Economic 60%

D Inflation 40 0 20 40

E Global Economic

Pressure 20 0 10 20

3. Technical 20%

F Project Specification 4 0 2 4

G Design Consideration 6 0 3 6

H Contract Period 2 0 1 2

J Project Management 2 0 1 2

L Form of Contract 6 0 3 6

Source: Association of America Cost Engineers International, 2008.

Table 4. Agreement between building professionals regarding factors influencing the determination of

contingency sum.

Factors Q uantity Surveyors

Architects Civil Engineers

Sum of Ranking (Ri)

Mean of Ranking (Ř)

Ri - Ř Ri -Ř)2 O ver All

Ranking

Economic 70 60 55 185 61.67 26.67 711 1st

Environmental / Institutional

25 25 15 65 21.67 -13.33 178 2nd

Technical 20 20 25 65 21.6 -13.33 178 2nd

Results and Discussions

Construction professionals were asked to rate factors, influencing, contingency sum in percentage terms as indicated in Table 3. The survey revealed that, professionals in the construction industry classify the factors, influencing the determination of contingency sum into technical, economic and environmental/ institutional factors. Technical factors were considered as Project Specification, Design Consideration, Contract Period, Project Management and Form of Contract. Economic

Factors included inflation and global economic pressure. Environmental factors included demand for extractive materials, force majeure and institutional factors included Social and cultural Impacts on project delivery in Ghana as shown in the flow chart of Fig. 1. In order to simplify the proposed method environmental and institutional factors were combined. Also some of these factors really do occur. According to the survey, construction professionals have all the abilities to manage the impact of technical factors in order to reduce the risk on contingency sum.

270 RICHARD ODURO ASAMOAH ET AL.

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ESTIMATING CO NTINGENCY SUM FOR BUILDING WORKS IN GHANA 271

Fig. 2. The Proposed Method of Estimating Contingency Sum (Contingency Calculator)

The study confirms that with proper planning

from the conception stage, the impact of technical factors could be reduced to the minimum. The professionals agreed to rate technical factor at 20%. The survey also revealed that, environmental/institutional factors also contribute to risk in construction. In Ghana, apart from occasional flooding experience, volcanic eruption, earth quake, landslide, etc rarely do occur. Recurrent cultural developments in Ghana have shown that there is the need to consider these factors. Sometimes, some traditional leaders demand huge compensation before allowing projects to commence. Building Professionals were to rate environmental/cultural factors at 20% of the contract contingency sum. The study also revealed that, professionals have no control over the economic factors. All the selected professionals agreed to rate economic factors at 60%. It is in the domain of the central

government to regulate the economic factors. Table 3 shows the rating and the agreement of factors amongst professionals in the construction industry.

Grand mean Ř = (n

i 1

Ri) 1/n = 35.00

∑(Ri –Ř)2 = 1,067

where Ri is the mean of rankings and ‘n’ is the number of factors being ranked.

Table 3 consists of factors and ratings influencing the determination of contingency. The factors and ratings were first developed by the Association of American Cost Engineers International (2008). The factors and the ratings were adopted for the purposes of the study to develop a flow chart for the new method of determining contingency sum (Fig. 1).

272 RICHARD ODURO ASAMOAH ET AL.

The proposed method was used to calculate the contingency sums for 38 selected building projects from Ashanti and Brong Ahafo regions as indicated in Table 6. The results and discussions were based on Table 6. Fifteen (15) projects had contingency figures by the proposed method to be higher than the actual contingency figures. Ten projects were ±5% close to the actual contingency figures and five of the projects were more than +5 the actual contingency figures. Seventeen of the selected projects had contingency figures by the proposed method to be less than the actual contingency figures. Nine of these projects were ± 5% close to the actual figures and eight of the projects were less than -5% from the actual contingency figures. Six projects were considered to have marginal percentage figures of ± 2% of the actual contingency figures. An assumption of ±5 was used to analyse the level of accuracy. Table 5 shows the outcome of the use of the proposed new Method. The table indicates that, the existing method had a contingency figure of ranging 2.5% - 10% with an average figure of 6.97%. The -5 gave a range of -2.5 - 5% with an average figure of 2.11%. And + 5 also gave a range of 7.5-15%, with an average figure of 11.79. The proposed Method gave a range of 10.2 -22.8% with an average figure of 14.54%. The -5% of the proposed method gave a range of 5.2-17.8%, with an average figure of 9.54, while the +5 gave a range of 4.5-41%, with an average figure of 15.75%. The existing method had an average contingency figure of 6.97%, 14.54% for the proposed Method and 15.75% for the actual contingency. This indicated that, the proposed

method gave an accurate figure compared to the actual than the existing method. Using the range of ±5%, the percentage Approach Method gave an average contingency figure of 2.11% and the proposed method had an average figure of 9.54%. This implied that the proposed method could be more accurate than the percentage approach method. The +5% also gave 11.79% for the Percentage Approach Method, 19.54 for the proposed method and + 5% to the actual average contingency figure was 20.75%. In comparison, the proposed method could be reliable. Table 5 showed that, the projects in items 21 and 22 had contingency figures of 2.5% each and after the completion of the projects the actual contingency was 4.8% and 4.5% respectively indicating 92% and 80 % increase in contingency sum using the Percentage Approach Method. However, the proposed method gave initial contingency figures of 10.2% and 10.8%. This suggests that, there would be enough to address unforeseen events and resources which were not be used would be reserved for future expenditures. Items 23, 27 and 33 had contingency by the Percentage Approach as 5%, 5% and 4.7%, respectively, and contingency figures from the proposed method gave 21.8%, 20.6% and 20.4% respectively. However, the actual contingency figures of 41%, 35.5% and 31.8% and were high above the initial percentage and the proposed contingency figures. In percentage terms, the actual contingency figures were 88%, 72.5% and 55.9%, respectively, high, but it could be said that the contingency figures by the Proposed Method were more accurate than the figures from the Percentage Approach Method.

Table 5. Selected projects under the building contracts with the respective contingency figure.

Item Project Estimated

(%)

Proposed Method (%)

Actual

(%) Difference

A B C D E = D – B F = D – C

1. HIPC/GETFUND - Construction of Day Care, Clinic

Post Office for Bosomtwi Atwima Kwanwoma District. 10 12.8 11 1 -1.8

2. BESP 5 No 6 unit Classroom Block and 10 unit 3-seater

K.V.I.P-Adansi District – Ashanti Region BESP-1 10 12.8 13 3 0.2

3. BESP 6 No 6 unit Classroom Block and 12 unit 3-seater

K.V.I.P-Offinso District – Ashanti Region BESP-2 10 16.4 15 5 -1.4

4. Basic Education Support Projects 5 No 6 unit classroom

Block and 10 unit 3-seater K.V.I.P-Sekyere West

District

10 12 15 5 3

5. PERP – Construction of Classroom blocks and Ancillary

Facility 10 14 12 2 -2

ESTIMATING CO NTINGENCY SUM FOR BUILDING WORKS IN GHANA 273

6. PPTAP - Construction of 6-unit Teachers’ Quarters-

Offinso District. 7.5 15 13 5.5 -2

7. PPTAP - Construction of 4-unit Teachers’ Quarters-

Offinso District

10 15 16 6 1

8. PPTAP - Construction of 3-unit Teachers’ Quarters-

Offinso District. 10 15 14 4 -1

9. PPTAP - Re-roofing of Yaa Asantewaah Basic School -

Kumasi

10 13.4 15 5 1.6

10. RUSCS – Construction of 2-storey boys Dormitory-

Effiduase Secondary Commercial School 10 13.4 8.5 -1.5 -4.9

11. HIPC/GETFUND – Construction of 6-unit classroom

Block - Kumasi 4.76 12.4 15 10.24 2.6

12. HIPC/GETFUND – Construction of Day Care center at

Old Amokom

5 13 15 10 2

13. HIPC/GETFUND - Construction of 6- unit classroom

Block- Ahamadiya Basic School Kumasi 4.76 14.4 17 12.24 2.6

14. HIPC/GETFUND - Construction of 2-Room Day Care,

for Bosomtwi Atwima Kwawoma District.

7 14.4 10 3 -4.4

15. HIPC/GETFUND - Construction of 2-Room Day Care in

bricks, for Bosomtwi Atwima Kwanwoma District. 5 13.4 10 5 -3.4

16. HIPC/GETFUND - Construction of 3-unit classroom

Block Bosomtwi Atwima Kwanwoma District. 5 12.4 12 7 -0.4

17. HIPC/GETFUND - Construction of 2-storey Post Office

and Stores - Kuntenase

5 10.4 7 2 -3.4

18. HIPC/GETFUND - Construction of Community Library

– AME ZION Amokom- Kumasi 5 14.4 15 10 0.6

19. HIPC/GETFUND - Construction of 7-unit classroom

Block - Amankwatia Kumasi

5 22.8 30 25 7.2

20. HIPC/GETFUND - Construction of Clinic for Bosomtwi

Atwima Kwanwoma District.

10 17.2 21 11 3.8

21. BESP 5 No 6 unit classroom Block and 10 unit 3-seater

K.V.I.P- Asutifi District – Brong Ahafo Region BESP-1

2.5 10.2 4.8 2.3 -5.4

22. BESP 6 No 6 unit classroom Block and 12 unit 3-seater

K.V.I.P- Asunafo District – Brong Ahafo Region BESP-

2

2.5 10.8 4.5 2 -6.3

23. RUSCS – Construction of 2 No Masters Bungalow

Dormitory- Effiduase Secondary Commercial School

5 21.8 41 36 19.2

24. RUSCS – Construction of 2-bedroom 3-storey Masters

Flat - Effiduase Secondary Commercial School

9 11 9.7 0.7 -2.0

25. RUSCS – Construction of 2-storey Classroom block -

Effiduase Secondary Commercial School

9 10.2 8.9 -0.1 -1.3

26. RUSCS – Construction of 2-storey boys Dormitory-

Effiduase Secondary Commercial School

9 20.8 26.4 17.4 5.6

27. RUSCS – Construction of 2-storey Girls’ Dormitory-

Effiduase Secondary Commercial School.

10 20.6 35.5 25.5 14.9

28. RUSCS – Construction of Assembly Hall - Effiduase

Secondary Commercial School

10 12.8 10.6 0.6 -2.2

29. RUSCS – Construction of New Dining Hall – Effiduase

Secondary Commercial School

5 16.8 21 16 4.2

30. RUSCS – Construction of Science Laboratory -

Effiduase Secondary Commercial School

5 15 22 17 7

31. RUSCS – Construction of Clinic - Effiduase Secondary

Commercial School

5 12.5 18 13 5.5

32. HIPC/GETFUND - Construction of 6-unit classroom

Block - Asokore Manpong - Kumasi Metropolitan

Assembly

5 10.4 7 2 -3.4

33. HIPC/GETFUND - Construction of 2-Room Day Care,

for Kumasi Metropolitan Assembly

4.7 20.4 31.8 27.1 11.4

34. HIPC/GETFUND - Construction of 2-Room Day Care in 9 22.8 25.7 16.7 2.9

274 RICHARD ODURO ASAMOAH ET AL.

bricks, for Ejisu – Juaben Municipal Assembly.

35. HIPC/GETFUND - Construction of 6-unit classroom

Block Ejisu – Juaben Municipal Assembly

5 14.8 13.1 8.1 -1.7

36. HIPC/GETFUND - Construction of Community Clinic

at Fenesu – Adansi Central District.

5 13.4 6.7 1.7 -6.7

37. HIPC/GETFUND - Construction of Community Library

– Kumasi

5 13.4 26.3 21.3 12.9

Average 6.97 14.54 15.75

Standard Deviation 2.36 4.58 10.94

Table 6. Comparison contingency figures using the Percentage Approach and the Proposed Method and Actual.

Item Percentage Addition

Existing Method

Proposed New Method

Actual

-5% +5% -5% +5% %

1 5 10 15 7.8 12.8 17.8 11

2 5 10 15 7.8 12.8 17.8 13

3 5 10 15 11.4 16.4 21.4 15

4 5 10 15 7 12 17 15

5 5 10 15 9 14 19 12

6 2.5 7.5 12.5 10 15 20 13

7 5 10 15 10 15 20 16

8 5 10 15 10 15 20 14

9 5 10 15 8.4 13.4 18.4 15

10 5 10 15 8.4 13.4 18.4 8.5

11 -0.24 4.76 9.76 7.4 12.4 17.4 15

12 0 5 10 8 13 18 17

13 -0.24 4.76 9.76 9.4 14.4 19.4 10

14 2 7 12 9.4 14.4 19.4 10

15 0 5 10 8.4 13.4 18.4 10

16 0 5 10 7.4 12.4 17.4 12

17 0 5 10 5.4 10.4 15.4 7

18 0 5 10 9.4 14.4 19.4 15

19 0 5 10 17.8 22.8 27.8 30

20 5 10 15 12.2 17.2 22.2 21

21 -2.5 2.5 7.5 5.2 10.2 15.2 4.8

22 -2.5 2.5 7.5 5.8 10.8 15.8 4.5

23 0 5 10 16.8 21.8 26.8 41

24 4 9 14 6 11 16 9.7

25 4 9 14 5.2 10.2 15.2 8.9

26 4 9 14 15.8 20.8 25.8 26.4

27 5 10 15 15.6 20.6 25.6 35.5

28 5 10 15 7.8 12.8 17.8 10.6

29 0 5 10 11.8 16.8 21.8 21

30 0 5 10 10 15 20 22

31 0 5 10 7.5 12.5 17.5 18

32 0 5 10 5.4 10.4 15.4 7

33 0.3 4.7 9.7 15.4 20.4 25.4 31.8

34 4 9 14 17.8 22.8 27.8 25.7

35 0 5 10 9.8 14.8 19.8 13.1

36 0 5 10 8.4 13.4 18.4 6.7

37 0 5 10 8.4 13.4 18.4 26.3

38 0 5 10 5.4 10.4 15.4 5.9

Average 2.11 6.97 11.79 9.54 14.54 19.54 15.75

ESTIMATING CO NTINGENCY SUM FOR BUILDING WORKS IN GHANA 275

Conclusions

The focus of this study was to identify more scientific method of determining contingency for

the building industry. The construction industry has different methods of determining contingency sum for building works which include Monte Carlo Simulation, Range Estimation and Estimating Using Risk. However, in Ghana, particularly in the Ashanti and Greater Accra regions, building professionals have been using the Percentage Approach and the Probability Estimation. The study concludes by developing a more scientific method than the previous methods of determining contingency sum. The new method is devoid of subjectivity and gives more accurate contingency figures. The introduction of the new method will help building professionals to manage the causes of variation orders and the uses of contingency sum.

Recommendations

Proper feasibility studies have been identified as the main source of information for the commencement of any project. Therefore, it is recommended that, every project should commence from the feasibility stage which should include all stakeholders in a project. This will help to limit changes in design during the construction stage. The study also identified that building professionals in Ghana have been using the Percentage Approach and the Probability Estimation, which have been found to be subjective. It is, therefore, recommended that building professionals should use other methods, such as, the Monte Carlo Simulation, Range Estimation and Estimating Using Risk Analysis and other methods in order to check for accuracy of contingency sums. Finally, further studies should be done in the road sector in order to determine the possibility of using scientific method determining contingency sum for the construction industry in Ghana.

References

Association of America Cost Engineers International. 2008. Risk Analysis and Contingency Using Range Estimation.

Baccarini, D. 2005. Understanding Project Cost Contingency – A survey Conference Proceedings, Construction Research of the Royal Institute of Chartered Surveyors- 4-8th July 2005 at Queensland University of Technology Brisbane, Australia.

Badu, E. 2004. Risk Sharing in Ghanaian Construction Contracts. The Ghanaian Surveyor Journal of Ghana Institution of Surveyors. Vol. 1. 2004, pp 1-12.

Davey, K. 1992. Conservation Contracts and Grant Aid, Practical Guide pp 941

st Edition.

London: E & FN Spon.

Ford, D.N. 2002. Achieving multiple project objectives through contingency management. Journal of Construction Engineering and Management, 128 (1), PP 30-37.

Ghana Poverty Reduction project/Social Investment Fund (GPRP/SIF), 2004: Final Report.

Kendall, M.G. 1970. Rank correlation methods. Griffin, London. (4

th Edition).

Kish, L. 1965. Survey Sampling. John Wiley and Sons Inc. New York.

Mak, S. and D. Picken. 2001. Using risk analysis to determine construction project cost contingencies. Journal of Construction Engineering and Management, Vol. 126, pp.130-6.

Tawiah, O. 1999. Factors Affecting the Performance of Ghanaian Owned Construction Firms (Unpublished).