Cost Modeling from the Contractor Perspective: Application to Residential and Office Buildings
Abstract
:1. Introduction
2. Literature Review
3. Data and Methods
4. Results and Discussion
4.1. Preliminary Data Analysis
4.2. Data Modeling
5. Conclusions
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Conflicts of Interest
References
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Reference | [21] | [22] | [23] | [24] | [25] | [26] | [27] | [28] | [29] | [30] | [31] | [32] | [33] |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Method | |||||||||||||
Regression Analysis | X | X | X | X | X | X | X | X | X | ||||
Artificial Neural Network | X | X | X | X | |||||||||
Case-Based Reasoning | X | ||||||||||||
Other | X | ||||||||||||
Variables | |||||||||||||
Project related | |||||||||||||
Building type | X | X | X | X | |||||||||
Area | X | X | X | X | X | X | X | X | |||||
Number of stories | X | X | X | X | X | ||||||||
Number of households | X | ||||||||||||
Height | X | X | X | X | X | ||||||||
Duration | X | X | X | X | X | ||||||||
Location | X | X | |||||||||||
Above ground external envelope characteristics | X | X | X | ||||||||||
Underground external envelope characteristics | X | X | |||||||||||
Number of lifts | X | X | X | ||||||||||
Number of piloti floors | X | ||||||||||||
Structural characteristics | X | ||||||||||||
Other | X | X | X | X | X | X | |||||||
Management related | |||||||||||||
Type of contract | X | X | X | ||||||||||
Procurement strategy | X | X | X | X | |||||||||
Other | X | X | |||||||||||
Other | |||||||||||||
Type of client | X | X | |||||||||||
Construction year | X | X | |||||||||||
Designer characteristics | X | ||||||||||||
Contractor characteristics | X | ||||||||||||
Site characteristics | X | ||||||||||||
Sample | |||||||||||||
Size | 15 | 30 | 288 | 36 | 50 | 93 | - | 30 | 290 | 42,340 18,469 | 75 | 91 | 232 |
Type | R | S | R | - | O | R O | R | R |
Variable | Sample | Range | Minimum | Maximum | Sum | Mean | Std. Dev. | Skewness | Kurtosis | |
---|---|---|---|---|---|---|---|---|---|---|
Floors (-) | Underground | 19 | 4 | 1 | 5 | 64 | 3.37 | 1.065 | −0.849 | 1.152 |
Above Ground | 21 | 20 | 3 | 23 | 153 | 7.29 | 4.880 | 2.162 | 4.987 | |
Total | 19 | 16 | 5 | 21 | 189 | 9.95 | 3.837 | 1.424 | 2.528 | |
Ratio | 19 | 6.25 | 0.75 | 7.00 | 42.48 | 2.24 | 1.531 | 1.944 | 4.278 | |
Area (m2) | Underground | 22 | 16,893.00 | 420.00 | 17,313.00 | 131,353.75 | 5970.63 | 4184.18 | 0.905 | 0.926 |
Above Ground | 22 | 10,342.00 | 1557.00 | 11,899.00 | 142,095.44 | 6458.88 | 2983.97 | 0.221 | −0.740 | |
Total | 23 | 26,136.00 | 1977.00 | 28,113.00 | 294,621.19 | 12,809.62 | 6671.70 | 0.287 | −0.311 | |
Ratio | 22 | 3.08 | 0.62 | 3.71 | 33.14 | 1.51 | 0.833 | 0.935 | 0.661 | |
Cost Category Weight (%) | Structure | 23 | 20.00 | 12.70 | 32.70 | 540.30 | 23.49 | 5.019 | −0.237 | −0.398 |
Architecture | 23 | 25.10 | 29.60 | 54.70 | 955.70 | 41.55 | 7.751 | −0.128 | −1.420 | |
Technical Installations | 23 | 24.90 | 9.50 | 34.40 | 532.60 | 23.16 | 6.822 | −0.425 | −0.449 | |
Site Overheads | 23 | 12.50 | 7.50 | 20.00 | 263.40 | 11.45 | 2.988 | 1.598 | 2.854 | |
Total Cost Index (-) | 21 | 21 | 2.11 | 0.19 | 2.29 | 21.00 | 0.126 | 0.333 | 0.501 | |
Margin Index (-) | 21 | 21 | 1.96 | 0.36 | 2.32 | 21.00 | 0.134 | 0.375 | 0.501 | |
Price (-) | Initial | 22 | 19,367,364.57 | 1,477,203.03 | 20,844,567.61 | 185,850,166.26 | 8,447,734.83 | 5,107,220.52 | 0.873 | 0.610 |
Final | 16 | 19,159,444.23 | 2,746,435.50 | 21,905,879.73 | 155,809,085.39 | 9,738,067.84 | 5,404,338.41 | 0.970 | 0.421 | |
Unit Price (-) | Initial | 22 | 1401.44 | 429.25 | 1830.69 | 15,022.83 | 682.86 | 288.56 | 3.239 | 12.577 |
Final | 16 | 1441.43 | 402.96 | 1844.39 | 11,576.50 | 723.53 | 343.78 | 2.563 | 7.779 | |
Cost Deviation (%) | 15 | 15 | 38.06 | −13.41 | 24.66 | 57.00 | 2.153 | 69.507 | 0.580 | |
Duration (days) | 23 | 23 | 240 | 240 | 480 | 7320 | 14.109 | 4578.656 | 0.481 |
Variables | Levene’s Test | t-Test | Difference | |||||||
---|---|---|---|---|---|---|---|---|---|---|
F | Sig. | t | Df | Sig. (2-Tailed) | Mean | Std. Error | 95% Confidence Interval | |||
Lower | Upper | |||||||||
Structure | EVA | 0.018 | 0.894 | 2.176 | 19 | 0.042 | 4.557 | 2.094 | 0.174 | 8.940 |
EVNA | 2.177 | 18.834 | 0.042 | 4.557 | 2.093 | 0.173 | 8.941 | |||
Architecture | EVA | 0.007 | 0.935 | −5.043 | 19 | 0.000 | −11.906 | 2.361 | −16.848 | −6.965 |
EVNA | −5.043 | 18.801 | 0.000 | −11.906 | 2.361 | −16.852 | −6.961 | |||
Technical Installations | EVA | 1.459 | 0.242 | 4.970 | 19 | 0.000 | 9.801 | 1.972 | 5.673 | 13.929 |
EVNA | 5.070 | 17.367 | 0.000 | 9.801 | 1.933 | 5.729 | 13.873 | |||
Site Overheads | EVA | 3.285 | 0.086 | −1.802 | 19 | 0.087 | −1.725 | 0.957 | −3.727 | 0.278 |
EVNA | −1.866 | 13.814 | 0.083 | −1.725 | 0.924 | −3.710 | 0.261 | |||
Unit Cost | EVA | 0.941 | 0.346 | −2.042 | 17 | 0.057 | −86.404 | 42.314 | −175.679 | 2.871 |
EVNA | −2.174 | 16.949 | 0.044 | −86.404 | 39.749 | −170.286 | −2.522 | |||
Initial Unit Price | EVA | 0.174 | 0.681 | −2.222 | 18 | 0.039 | −100.576 | 45.273 | −195.692 | −5.460 |
EVNA | −2.222 | 17.920 | 0.039 | −100.576 | 45.273 | −195.722 | −5.430 | |||
Final Unit Price | EVA | 0.054 | 0.821 | −1.412 | 12 | 0.183 | −106.575 | 75.453 | −270.974 | 57.823 |
EVNA | −1.443 | 11.650 | 0.175 | −106.575 | 73.854 | −268.029 | 54.878 |
Variables | Levene’s Test | t-Test | Difference | |||||||
---|---|---|---|---|---|---|---|---|---|---|
F | Sig. | t | df | Sig. (2-Tailed) | Mean | Std. Error | 95% Confidence Interval | |||
Lower | Upper | |||||||||
All buildings | ||||||||||
Structure | EVA | 2.616 | 0.122 | −0.653 | 19 | 0.521 | −1.924 | 2.944 | −8.085 | 4.238 |
EVNA | −0.445 | 3 | 0.683 | −1.924 | 4.325 | −14.782 | 10.935 | |||
Architecture | EVA | 0.026 | 0.874 | 1.349 | 19 | 0.193 | 5.919 | 4.387 | −3.262 | 15.100 |
EVNA | 1.187 | 4 | 0.301 | 5.919 | 4.988 | −7.919 | 19.757 | |||
Technical Installations | EVA | 3.737 | 0.068 | −1.141 | 19 | 0.268 | −4.199 | 3.680 | −11.901 | 3.504 |
EVNA | −2.048 | 17 | 0.056 | −4.199 | 2.050 | −8.523 | 0.126 | |||
Site Overheads | EVA | 1.252 | 0.277 | −0.203 | 19 | 0.841 | −0.268 | 1.316 | −3.021 | 2.486 |
EVNA | −0.322 | 11 | 0.753 | −0.268 | 0.832 | −2.090 | 1.554 | |||
Unit Cost | EVA | 0.055 | 0.818 | 1.566 | 17 | 0.136 | 83.700 | 53.461 | −29.092 | 196.492 |
EVNA | 1.610 | 5 | 0.169 | 83.700 | 51.981 | −50.578 | 217.979 | |||
Initial Unit Price | EVA | 0.290 | 0.597 | 2.396 | 18 | 0.028 | 133.254 | 55.626 | 16.388 | 250.119 |
EVNA | 2.392 | 5 | 0.066 | 133.254 | 55.701 | −13.522 | 280.029 | |||
Final Unit Price | EVA | 0.938 | 0.352 | 1.959 | 12 | 0.074 | 152.192 | 77.701 | −17.105 | 321.488 |
EVNA | 2.284 | 8 | 0.052 | 152.192 | 66.628 | −1.443 | 305.826 | |||
Office Buildings | ||||||||||
Structure | EVA | 1.605 | 0.241 | −1.536 | 8 | 0.163 | −4.719 | 3.072 | −11.802 | 2.364 |
EVNA | −2.222 | 8 | 0.058 | −4.719 | 2.124 | −9.633 | 0.195 | |||
Architecture | EVA | 3.441 | 0.101 | 1.216 | 8 | 0.259 | 4.424 | 3.638 | −3.966 | 12.813 |
EVNA | 1.703 | 8 | 0.127 | 4.424 | 2.597 | −1.566 | 10.414 | |||
Technical Installations | EVA | 3.395 | 0.103 | 0.829 | 8 | 0.431 | 2.014 | 2.431 | −3.592 | 7.620 |
EVNA | 0.980 | 6 | 0.366 | 2.014 | 2.055 | −3.049 | 7.078 | |||
Site Overheads | EVA | 4.993 | 0.056 | −2.723 | 8 | 0.026 | −1.719 | 0.631 | −3.175 | −0.263 |
EVNA | −2.075 | 2 | 0.148 | −1.719 | 0.828 | −4.695 | 1.257 | |||
Unit Cost | EVA | 6.878 | 0.039 | 2.612 | 6 | 0.040 | 98.267 | 37.628 | 6.195 | 190.340 |
EVNA | 3.385 | 5 | 0.022 | 98.267 | 29.034 | 21.891 | 174.643 | |||
Initial Unit Price | EVA | 10.343 | 0.012 | 3.140 | 8 | 0.014 | 150.429 | 47.907 | 39.956 | 260.901 |
EVNA | 4.614 | 8 | 0.002 | 150.429 | 32.605 | 74.662 | 226.195 | |||
Final Unit Price | EVA | 2.021 | 0.228 | 2.465 | 4 | 0.069 | 181.754 | 73.733 | −22.961 | 386.469 |
EVNA | 2.465 | 3 | 0.088 | 181.754 | 73.733 | −49.712 | 413.220 |
Variables | Structure | Architecture | Technical Installations | Site Overheads | Total Cost | Initial Price | Final Price | Unit Cost | Initial Unit Price | Final Unit Price | Cost Deviation | |
---|---|---|---|---|---|---|---|---|---|---|---|---|
Structure | Correlation | −0.425 ** | 0.005 | −0.135 | 0.340 * | 0.417 * | 0.376 | −0.270 | −0.153 | −0.221 | −0.013 | |
Sig. (2-tailed) | 0.007 | 0.976 | 0.397 | 0.042 | 0.010 | 0.062 | 0.107 | 0.347 | 0.273 | 0.951 | ||
N | 21 | 21 | 21 | 19 | 20 | 14 | 19 | 20 | 14 | 13 | ||
Architecture | Correlation | −0.543 ** | 0.053 | −0.216 | −0.253 | −0.143 | 0.322 | 0.253 | 0.319 | −0.077 | ||
Sig. (2-tailed) | 0.001 | 0.739 | 0.196 | 0.119 | 0.477 | 0.054 | 0.119 | 0.112 | 0.714 | |||
N | 21 | 21 | 19 | 20 | 14 | 19 | 20 | 14 | 13 | |||
Technical Installations | Correlation | −0.302 | 0.205 | 0.221 | −0.011 | −0.216 | −0.200 | −0.209 | −0.128 | |||
Sig. (2-tailed) | 0.057 | 0.221 | 0.173 | 0.956 | 0.196 | 0.218 | 0.298 | 0.542 | ||||
N | 21 | 19 | 20 | 14 | 19 | 20 | 14 | 13 | ||||
Site Overheads | Correlation | 0.413 * | 0.483 ** | −0.331 | 0.012 | 0.005 | −0.044 | 0.297 | ||||
Sig. (2-tailed) | 0.014 | 0.003 | 0.100 | 0.944 | 0.974 | 0.826 | 0.160 | |||||
N | 19 | 20 | 14 | 19 | 20 | 14 | 13 | |||||
Underground Floors | Correlation | 0.336 | 0.062 | −0.109 | −0.314 | 0.108 | 0.280 | 0.238 | −0.088 | −0.140 | −0.089 | 0.149 |
Sig. (2-tailed) | 0.079 | 0.744 | 0.568 | 0.102 | 0.596 | 0.142 | 0.296 | 0.664 | 0.463 | 0.695 | 0.514 | |
N | 18 | 18 | 18 | 18 | 16 | 18 | 13 | 16 | 18 | 13 | 13 | |
Above Ground Floors | Correlation | −0.286 | 0.380 * | −0.063 | −0.089 | −0.090 | −0.064 | 0.082 | 0.008 | −0.049 | 0.151 | 0.162 |
Sig. (2-tailed) | 0.106 | 0.031 | 0.719 | 0.615 | 0.638 | 0.726 | 0.696 | 0.966 | 0.785 | 0.469 | 0.456 | |
N | 19 | 19 | 19 | 19 | 17 | 18 | 14 | 17 | 18 | 14 | 13 | |
Total Floors | Correlation | −0.098 | 0.327 | −0.132 | −0.183 | −0.036 | 0.021 | 0.211 | −0.072 | −0.104 | 0.053 | 0.184 |
Sig. (2-tailed) | 0.587 | 0.069 | 0.461 | 0.313 | 0.853 | 0.907 | 0.325 | 0.710 | 0.561 | 0.806 | 0.389 | |
N | 18 | 18 | 18 | 18 | 16 | 18 | 13 | 16 | 18 | 13 | 13 | |
Underground Area | Correlation | 0.558 ** | −0.495 ** | 0.286 | −0.273 | 0.579 ** | 0.663 ** | 0.473 * | −0.520 ** | −0.389 * | −0.516 * | −0.051 |
Sig. (2-tailed) | 0.000 | 0.002 | 0.070 | 0.085 | 0.001 | 0.000 | 0.019 | 0.002 | 0.016 | 0.010 | 0.807 | |
N | 21 | 21 | 21 | 21 | 19 | 20 | 14 | 19 | 20 | 14 | 13 | |
Above Ground Area | Correlation | 0.431 ** | −0.100 | −0.005 | −0.327 * | 0.739 ** | 0.691 ** | 0.758 ** | −0.246 | −0.216 | −0.231 | 0.000 |
Sig. (2-tailed) | 0.007 | 0.526 | 0.976 | 0.040 | 0.000 | 0.000 | 0.000 | 0.141 | 0.183 | 0.250 | 1.000 | |
N | 21 | 21 | 21 | 21 | 19 | 20 | 14 | 19 | 20 | 14 | 13 | |
Total Area | Correlation | 0.539 ** | −0.362 * | 0.171 | −0.350 * | 0.743 ** | 0.800 ** | 0.714 ** | −0.427 * | −0.358 * | −0.407 * | 0.000 |
Sig. (2-tailed) | 0.001 | 0.022 | 0.277 | 0.027 | 0.000 | 0.000 | 0.000 | 0.011 | 0.027 | 0.043 | 1.000 | |
N | 21 | 21 | 21 | 21 | 19 | 20 | 14 | 19 | 20 | 14 | 13 | |
Area Ratio | Correlation | 0.539 ** | −0.362 * | 0.171 | −0.350 * | 0.743 ** | 0.800 ** | 0.714 ** | −0.427 * | −0.358 * | −0.407 * | 0.000 |
Sig. (2-tailed) | 0.001 | 0.022 | 0.277 | 0.027 | 0.000 | 0.000 | 0.000 | 0.011 | 0.027 | 0.043 | 1.000 | |
N | 21 | 21 | 21 | 21 | 19 | 20 | 14 | 19 | 20 | 14 | 13 |
Parameter | B | Robust Std. Error a | t | Sig. | 95% Confidence Interval | |
---|---|---|---|---|---|---|
Lower Bound | Upper Bound | |||||
Initial Price | ||||||
Above Ground Area (AGA) | 735.860 | 138.565 | 5.311 | 0.000 | 443.512 | 1028.207 |
Underground Area (UGA) | 462.428 | 121.467 | 3.807 | 0.001 | 206.155 | 718.701 |
Area X Crisis | −102.426 | 36.276 | −2.824 | 0.012 | −178.961 | −25.890 |
Final Price | ||||||
Above Ground Area | 1393.707 | 399.891 | 3.485 | 0.005 | 513.554 | 2273.860 |
Underground Area | 232.331 | 127.608 | 1.821 | 0.096 | −48.531 | 513.194 |
Area X Type | −181.507 | 118.842 | −1.527 | 0.155 | −443.077 | 80.062 |
Parameter | B | Robust Std. Error a | t | Sig. | 95% Confidence Interval | |
---|---|---|---|---|---|---|
Lower Bound | Upper Bound | |||||
Intercept | 503.309 | 36.238 | 13.889 | 0.000 | 425.022 | 581.596 |
Above Ground Floors 1.011 | −160.284 | 30.403 | −5.272 | 0.000 | −225.966 | −94.602 |
Total Floors 1.608 | 17.286 | 3.129 | 5.524 | 0.000 | 10.525 | 24.046 |
Floor Ratio | 117.935 | 25.915 | 4.551 | 0.001 | 61.949 | 173.920 |
Economic Crisis = 0 | 211.752 | 36.914 | 5.736 | 0.000 | 132.005 | 291.499 |
Economic Crisis = 1 | 0.000 |
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Monteiro, F.P.; Sousa, V.; Meireles, I.; Oliveira Cruz, C. Cost Modeling from the Contractor Perspective: Application to Residential and Office Buildings. Buildings 2021, 11, 529. https://doi.org/10.3390/buildings11110529
Monteiro FP, Sousa V, Meireles I, Oliveira Cruz C. Cost Modeling from the Contractor Perspective: Application to Residential and Office Buildings. Buildings. 2021; 11(11):529. https://doi.org/10.3390/buildings11110529
Chicago/Turabian StyleMonteiro, Francisco Pereira, Vitor Sousa, Inês Meireles, and Carlos Oliveira Cruz. 2021. "Cost Modeling from the Contractor Perspective: Application to Residential and Office Buildings" Buildings 11, no. 11: 529. https://doi.org/10.3390/buildings11110529