Fig. 1:
Fig. 2:
Comparison of the validity results of the regression, CHAID and CART methods_
| Statistical methods | Number of significant variables | Estimation | Standard error |
|---|---|---|---|
| Regression | 6 | 36,495.932 | 3,039.935 |
| CHAID | 5 | 37,227.186 | 3,109.763 |
| CART | 3 | 33,379.646 | 3,166.306 |
j_otmcj-2023-0014_tab_013
| Project No. | Construction project description | District | Number of flats | Number of working days with construction documents | Number of working days with schematic design | Number of non-working days | Contract duration (days) | Number of time extension | Delay (days) |
|---|---|---|---|---|---|---|---|---|---|
| 1 | North Ankara city entrance 7th stage 318 houses, 1 commercial centre, infrastructure and landscaping | Altindağ | 318 | 500 | 550 | 145 | 505 | 1 | 0 |
| 2 | North Ankara city entrance villas 584 houses, 3 elementary schools, 1 kindergarten and mosque, infrastructure and landscaping | Altindağ | 584 | 500 | 550 | 388 | 554 | 1 | 681 |
| 3 | Elazig city centre 336 houses and social facilities (mosque, fountain, trade centre, library) infrastructure and landscaping | City centre | 336 | 500 | 550 | 120 | 365 | 1 | 0 |
| 4 | Isparta 96 houses, 1 trade centre, infrastructure and landscaping | Yalvaç | 96 | 400 | 450 | 90 | 504 | 0 | 0 |
| 5 | Karabük 2nd region 432 houses, 1 primary school, 2 trade centres, 1 mosque, infrastructure and landscaping | City centre | 432 | 500 | 550 | 105 | 44 | 1 | 359 |
| 6 | North Ankara city entrance 477 houses, infrastructure and landscaping | Altindağ | 477 | 500 | 550 | 165 | 651 | 1 | 0 |
| 7 | North Ankara city entrance 488 houses, 1 unit centre, 1 nursery, infrastructure and landscaping | Altindağ | 488 | 500 | 550 | 165 | 651 | 1 | 0 |
| 8 | North Ankara city entrance 799 houses, 1 unit centre, infrastructure and landscaping | Altindağ | 799 | 550 | 600 | 175 | 654 | 1 | 0 |
| 9 | Trabzon urban transformation project 96 houses, 1 health centre, infrastructure and landscaping | Çağlayan | 96 | 400 | 450 | 97 | 554 | 1 | 0 |
| 10 | Trabzon Çamli area 88 houses, infrastructure and landscaping | Of | 88 | 400 | 450 | 97 | 454 | 1 | 0 |
| 11 | Tunceli city centre Atatürk neighbourhood 222 houses, trade centre, infrastructure and landscaping | City centre | 222 | 400 | 450 | 150 | 483 | 1 | 0 |
| 12 | Ankara upper Yurtçu Kuyupınar area, 3rd region 1272 houses, 1 commercial centre, infrastructure and landscaping | City centre | 1,272 | 600 | 650 | 160 | 514 | 0 | 0 |
| 13 | North Ankara city entrance, 3rd stage 530 houses | Altindağ | 530 | 500 | 550 | 120 | 505 | 1 | 730 |
| 14 | North Ankara city entrance 341 villas, infrastructure and landscaping | Altindağ | 341 | 500 | 550 | 360 | 602 | 1 | 444 |
| 15 | Ankara 5th region 226 houses, 1 primary school, 1 high school, infrastructures and landscaping | Yapracik | 226 | 400 | 450 | 360 | 654 | 1 | 427 |
| 16 | Ankara 196 houses, trade centres, mosques, fountains, infrastructure and landscaping | Haymana | 196 | 400 | 450 | 360 | 554 | 1 | 451 |
| 17 | Antalya revenue sharing business for urban service area | Çiplakli | 406 | 500 | 550 | 0 | 548 | 1 | 478 |
| 18 | Antalya 892 houses, infrastructure and landscaping | Çiplakli | 892 | 550 | 600 | 0 | 395 | 1 | 539 |
| 19 | Bingöl 89 farm village houses, infrastructure and landscaping | Kiğı | 89 | 400 | 450 | 150 | 404 | 0 | 0 |
| 20 | Bolu city centre Paşaköy 2nd stage 500 houses, 1 commercial centre, health centre, infrastructure and landscaping | City centre | 500 | 500 | 550 | 240 | 454 | 1 | 211 |
Description of factors used to determine the total construction duration for public housing projects_
| Factors | Description of factors | Variable type |
|---|---|---|
| F1 + F2 + F3 (standardised) | BCD | Independent |
| F4 | Priority of project | Independent |
| F5 | Complexity of project | Independent |
| F6 | Special request for project | Independent |
| F7 | Difficulty of project | Independent |
| F8 | Financial risk of project | Independent |
| F9 | Logistic conditions of project region | Independent |
| F10 | Climatic conditions of project region | Independent |
| F11 | Seismicity of project region | Independent |
Findings of the three statistical methods_
| Variables | Regression | CHAID | CART |
|---|---|---|---|
| Standardised BCD (F1 + F2 + F3) | Significant | Significant | Significant |
| Priority of project (F4) | Significant | Significant | Significant |
| Complexity of project (F5) | Significant | - | - |
| Difficulty of project (F7) | Significant | - | - |
| Financial risk of project (F8) | Significant | - | - |
| Logistic conditions of project region (F9) | - | Significant | Significant |
| Climatic conditions of project region (F10) | Significant | Significant | - |
| Seismicity of project region (F11) | - | Significant | - |
| Special request for project (F6) | - | - | - |
Validity of the CHAID method_
| Method | Estimation | Standard error |
|---|---|---|
| CHAID | 37,227.186 | 3,109.763 |
| 10-fold cross-validation | 40,115.651 | 3,524.340 |
| Training set (70%) | 36,616.334 | 5,011.920 |
| Test set (30%) | 42,521.916 | 4,823.904 |
Results of the regression analysis_
| Variables | R2 | β | t | P | VIF |
|---|---|---|---|---|---|
| Regression method | 0.356 | 663.630 | 21.009 | 0.000** | |
| Standardised BCD (F1 + F2 + F3) | 146.447 | 27.833 | 0.000** | 1.160 | |
| Priority of project (F4) | –48.437 | –3.733 | 0.000** | 1.341 | |
| Complexity of project (F5) | –47.053 | –4.057 | 0.000** | 1.402 | |
| Special request for project (F6) | –0.029 | –1.249 | 0.212 | 1.279 | |
| Difficulty of project (F7) | 43.870 | 3.800 | 0.000** | 1.047 | |
| Financial risk of project (F8) | –18.510 | –2.326 | 0.020* | 1.011 | |
| Logistic conditions of project region (F9) | –3.953 | –1.716 | 0.086 | 1.088 | |
| Climatic conditions of project region (F10) | –13.676 | –4.768 | 0.000** | 1.045 | |
| Seismicity of project region (F11) | –0.024 | –1.205 | 0.228 | 1.115 |
Literature review of factors affecting construction duration_
| Authors | Factors affecting construction duration | Type of projects | Significance level |
|---|---|---|---|
| Kaka and Price (1991) | Project type, form and type of tender | Public buildings and civil engineering projects | |
| Chan and Kumaraswamy (1997) | Project characteristics, ground conditions, project design complexity, procurement scheduling and environmental factors | Building and civil works | |
| Kaming et al. (1997) | Weather conditions, project location, inadequate planning and project design | High-rise projects | |
| Chan and Kumaraswamy (2002) | Site condition, project characteristics, design aspects and pre-construction planning | Public housing, public non-residential buildings and private sector buildings | |
| Meeampol and Ogunlan (2006) | Construction method and schedule management | Highway construction projects | p = 0.000 |
| Hoffman et al. (2007) | Project cost, design/construction agent and temperature | Facility projects | p = 0.01, p = 0.0072 and p = 0.0028 |
| Salleh (2009) | Weather and site conditions, and inadequate planning | Residential, office, hotel, academic buildings and mosques | p < 0.05 |
| Mauriya et al. (2010) | Geological condition, seismicity and difficult terrain | Tunnel construction | |
| Doloi et al. (2012) | Client’s influence and improper planning | Construction projects | p = 0.000 and p = 0.003 |
| Dursun and Stoy (2012) | Project type, project location, availability of construction area and market conditions | Buildings | p < 0.05 |
| Shanmugapriya and Subramanian (2013) | Market conditions, contract modification and project location | Buildings, roads and bridges, industrial projects and others | – |
| Sweis (2013) | Planning and scheduling, and weather conditions | Public construction projects | – |
| Faremi et al. (2016) | Design and documentation issues, poor labour productivity and financial resource management | Construction projects | p < 0.05 |
| Oyedele (2017) | Cash flow, type of design (complexity), project type, topography and geology, supply chain management and weather | Construction projects | – |
| Nayak (2019) | Environmental conditions, equipment and cash flow | Rural infrastructure projects | – |
| Mahmoodzadeh et al. (2022) | Geological conditions and machinery | Tunnel construction | p = 0.000 |
Descriptive statistics for the ideal construction duration_
| Methods | Number | Average (days) | Standard deviation | Minimum |
|---|---|---|---|---|
| Regression | 1,530 | 679.16 | 133.20 | 387 |
| CHAID | 1,530 | 704.38 | 113.13 | 635 |
| CART | 1,530 | 705.98 | 109.50 | 640 |
Test results for the developed calculation method_
| Pre-test | Post-test | |
|---|---|---|
| Number of delayed housing projects | 40 | 23 |
| Delay percentage | 100% | 57.50% |
| Reduction amount of delayed housing projects (%) | 42.50 |
Results for the implementation of the proposed calculation method_
| Before implementation | After implementation | |||
|---|---|---|---|---|
| Number of delayed public housing projects | 720 | 350 | 285 | 299 |
| Percentage of delayed public housing projects (%) | 47.06 | 22.88 | 18.63 | 19.54 |
| Amount of decrease for delayed public housing projects (%) | 51.39 | 60.42 | 58.47 | |
Validity of the regression method_
| Group 1 (enter method) | Group 2 (stepwise method) | |||||
|---|---|---|---|---|---|---|
| B | t | p | β | t | p | |
| Regression variables | 696.696 | 18.876 | 0.000** | 646.473 | 21.562 | 0.000** |
| Standardised BCD (F1 + F2 + F3) | 146.765 | 27.548 | 0.000** | 148.020 | 28.551 | 0.000** |
| Priority of project (F4) | −55.102 | −3.981 | 0.000** | −50.401 | −3.897 | 0.000** |
| Complexity of project (F5) | −48.665 | −4.179 | 0.000** | −47.116 | −4.060 | 0.000** |
| Special request for project (F6) | −18.039 | −1.329 | 0.184 | −0.033 | −1.431 | 0.153 |
| Difficulty of project (F7) | 43.636 | 3.781 | 0.000** | 47.520 | 4.185 | 0.000** |
| Financial risk of project (F8) | −17.797 | −2.231 | 0.026* | −18.340 | −2.304 | 0.021* |
| Logistic conditions of project region (F9) | −4.285 | −1.800 | 0.072 | −0.037 | −1.716 | 0.086 |
| Climatic conditions of project region (F10) | −13.893 | −4.835 | 0.000** | −14.443 | −5.081 | 0.000** |
| Seismicity of project region (F11) | −5.978 | −1.205 | 0.228 | −0.014 | −0.680 | 0.496 |
List of factors affecting construction duration from the literature_
| No. | Factors | Factors encountered during the implementation stage | Factors encountered during the bidding stage | Factors caused by the contractor | Factors caused by the owner | Factors selected for the calculation method | Factors encountered during the bidding stage and caused by the owner | Authors |
|---|---|---|---|---|---|---|---|---|
| 1 | Delivery of material on time | + | – | + | – | – | – | Alaghbari et al. (2007), Asnaashari et al. (2009) and Tunji-Olayeni et al. (2018) |
| 2 | Productivity of labour | + | – | + | – | – | – | Faremi et al. (2016) and Smugala and Kubečková (2021) |
| 3 | Using an effective construction programme (schedule) | + | + | + | + | + | – | Chan and Kumaraswamy (2002), Sweis (2013) and Lines et al. (2015) |
| 4 | Design–implementation coordination | + | – | + | – | – | – | Faremi et al. (2016) |
| 5 | Recruitment of labour | + | – | + | – | – | – | Ahuja and Nandakumar (1985) |
| 6 | Changes in design | + | – | + | + | – | – | Shanmugapriya and Subramanian (2013) |
| 7 | Seismicity of project location | + | + | + | + | + | + | Mauriya et al. (2010) and Mahmoodzadeh et al. (2022) |
| 8 | Sufficient number and experience of management staff | + | – | + | – | – | – | Lo et al. (2006) |
| 9 | Selection of subcontractors | + | – | + | – | – | – | Polat et al. (2015) |
| 10 | Project type and features | – | + | + | + | + | – | Dursun and Stoy (2012) and Oyedele (2017) |
| 11 | Effective organisation structure | + | – | + | – | – | – | Arditi et al. (1985) |
| 12 | Company-based financial issues | + | + | + | – | – | – | Lo et al. (2006) and Nayak (2019) |
| 13 | Technology used in construction | + | + | + | + | + | – | Chan and Kumaraswamy (2002) |
| 14 | Ensuring business continuity | + | – | + | – | – | – | Alfalasi (2016) |
| 15 | Ensuring additional drawings, specifications and technical details provided on time | + | – | – | + | – | – | Ahuja and Nandakumar (1985) |
| 16 | Scope changes | + | – | – | + | – | – | Arditi et al. (1985) and Shanmugapriya and Subramanian (2013) |
| 17 | Maintaining coordination between subcontractors | + | – | + | – | – | – | Hwang et al. (2013) |
| 18 | Motivation of labour | + | – | + | – | – | – | Nasirzadeh and Nojedehi (2013) |
| 19 | Natural disasters | FM | – | FM | – | – | – | Nayak (2019) |
| 20 | Degree of project difficulty | + | + | + | + | + | + | Kaka and Price (1991), Chan and Kumaraswamy (1997), Chan and Kumaraswamy (2002) and Oyedele (2017) |
| 21 | Design-planning coordination | + | – | + | – | – | – | Walker and Vines (2000) |
| 22 | Efficient auditing and control | – | – | + | + | – | – | Long et al. (2008) |
| 23 | Delays in site handover | – | + | – | + | + | – | Iyer et al. (2008) |
| 24 | Rational use of construction equipment | + | – | + | – | – | – | Oleinik et al. (2019) |
| 25 | Having experienced staff during design phase | + | + | + | + | + | – | Oyewobi and Ogunsemi (2010) and Lessing et al. (2017) |
| 26 | Maintaining suitable site conditions | + | – | + | – | – | – | Dursun and Stoy (2012) |
| 27 | Implementation mistakes | + | – | + | – | – | – | Kaliba et al. (2009) |
| 28 | Extreme weather conditions | FM | – | FM | – | – | – | Kaming et al. (1997), Salleh (2009) and Oyedele (2017) |
| 29 | Sufficiency of design consultancy services | + | + | + | + | + | – | Le-Hoai et al. (2008) |
| 30 | Efficiency of engineers | + | – | + | + | – | – | Chan and Kumaraswamy (1995) |
| 31 | Selection of suitable construction equipment | + | – | + | – | – | – | Mahmoodzadeh et al. (2022) |
| 32 | Efficient use of information technologies | – | + | + | + | + | – | Li et al. (2005) |
| 33 | Experience in use of applied construction technology | + | – | + | – | – | – | Memon et al. (2012) |
| 34 | Equipment failures | + | – | + | – | – | – | Aibinu and Odeyinka (2006) and Mahmoodzadeh et al. (2022) |
| 35 | Excess bureaucracy | + | + | + | + | + | – | Abd El-Razek et al. (2008) |
| 36 | Adaptation to work and willingness to learn tasks | + | – | + | – | – | – | Doloi et al. (2012) |
| 37 | Selection of material | + | – | + | – | – | – | Koushki et al. (2005) |
| 38 | Financial risk of project | + | + | + | + | + | + | Arditi et al. (1985), Türesoy (1989), Hoffman et al. (2007) and Musarat et al. (2021) |
| 39 | Sufficiency of construction consultancy services | + | – | + | + | – | – | Alaghbari et al. (2007) and Hwang et al. (2013) |
| 40 | Claim issues and disputes between stakeholders | + | – | + | + | – | – | Al-Khalil and Al-Ghafly (1999) and Aibinu and Jagboro (2002) |
| 41 | Ground conditions and topography of construction site | + | + | + | + | + | – | Cheng, (2014) and Oyedele (2017) |
| 42 | Communication with other authorities | + | – | + | + | – | – | Doloi et al. (2012) and Hwang et al. (2013) |
| 43 | Changes in importance levels of activities | + | – | + | + | – | – | Woolery and Crandall (1983) and Nguyen et al. (2013) |
| 44 | Emergency plans for unforeseen conditions, risk, and crisis management plans | + | + | + | – | – | – | Hosseinian and Reinschmidt (2015) |
| 45 | Document control and management | + | – | + | – | – | – | Faremi et al. (2016) |
| 46 | Suitability of contract for project type | + | + | – | + | + | – | Oyedele (2017) |
| 47 | Using imported materials | + | + | + | + | + | – | Odeh and Battaineh (2002) |
| 48 | Material storage facilities | + | – | + | – | – | – | Kumar and Cheng (2015) |
| 49 | Project procedures | + | + | + | + | + | – | Williams (2008) |
| 50 | Quality control | + | – | + | + | – | – | Aliverdi et al. (2013) |
| 51 | Distance to construction site | + | + | + | + | + | – | Ramli et al. (2018) |
| 52 | Applied tax policies and government incentives to construction industry | + | – | – | – | – | – | Chan and Kumaraswamy (1995) and Girth and Lopez (2019) |
| 53 | Legislative changes and legal regulations | + | – | – | + | – | – | Ahuja and Nandakumar (1985) |
| 54 | Preparation of reliable project programme (schedule) | + | + | + | + | + | – | Meeampol and Ogunlan (2006) and Salleh (2009) |
| 55 | Cultural, religious and social factors in project location | + | + | + | + | + | – | Assaf and Al-Hejji (2006) and Al-Sabah et al. (2014) |
| 56 | Theft | + | – | + | – | – | – | Haas et al. (2022) |
| Total | 50 | 21 | 48 | 29 | 18 | 3 |
Validation of the CART method_
| Method | Estimation | Standard error |
|---|---|---|
| CART | 33,379.264 | 3,166.306 |
| 10-fold cross-validation | 41,092.216 | 3,860.222 |
| Training set (70%) | 43,341.801 | 5,111.257 |
| Test set (30%) | 41,189.758 | 5,133.594 |