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The current estimation practice in construction projects greatly needs upgrading, as there has been no improvement in the cost overrun issue over the past 70 years. The purpose of this research was to develop a new multiple regression analysis (MRA)-based model to forecast the final cost of road projects at the pre-design stage using data from 43 projects in New Zealand (NZ).

The research used the case study of 43 completed road projects in NZ. Document analysis was conducted to collect data, and statistical tests were used for model development and analysis.

Eight models were developed, and all models achieved the required F statistics and met the regression assumptions. The models’ mean absolute percentage error (MAPE) was between 21.25% and 22.77%. The model with the lowest MAPE comprised the road length and width, number of bridges, pavement area, cut and fill area, preliminary cost and cost indices change.

The model is based on road projects in NZ. However, it was designed to be able to adapt to other contexts. The findings suggest that the model can be used to improve traditional conceptual estimating methods. Past project data is often stored by the project team but rarely used for analysing and forecasting purposes. This research emphasises that past data can be effectively used to predict the project cost at the pre-design stage with limited information.

No research was conducted to adopt cost modelling techniques into the conceptual estimation practice in the NZ construction industry.

The development of prefabrication into full-scale offsite manufacturing processes in the construction industry is paradigm-shifting. Moreover, Building Information Modelling (BIM) is becoming the primary mode of communication and integration in construction projects to facilitate the flow of information. Although research has been performed on BIM and Offsite Construction (OSC), integrating these two concepts remains ambiguous and complex and lacks documentation and structure, especially in New Zealand. Therefore, this paper develops a robust framework for OSC and BIM integration. The study focusses on identifying integration challenges and proposes strategies for overcoming these challenges.

This study applied scientometric analysis, a systematic literature review (SLR) and semi-structured expert interviews to investigate OSC and BIM integration challenges. Multiple themes were investigated and triangulation conducted in this research supports the creation of applicable knowledge in this field.

Multiple gaps, research trends and the pioneer countries in the paper's scope have been identified through scientometric analysis. Then, a classified cluster of challenges for OSC and BIM implementation and integration strategies of OSC and BIM were demonstrated from the findings. The interviews provided comprehensive and complementary data sets and analyses. The findings from the Systematic Literature Review and interview structured the integration framework.

The contribution of this paper to existing knowledge is a developed framework that serves as a guideline for the OSC stakeholders. This framework can assess OSC's alignment with BIM and consolidate strategies for incorporating OSC into a BIM-based project delivery process. The framework consists of 23 strategies categorised into 8 clusters: a policy document, training and professional development, documentation, technology management, governmental development, contract development, accurate definition and detailing and communication. The proposed strategies will streamline integration by reducing potential challenges, thus enhancing project productivity.

The construction industry's transformation of prefabrication into large-scale offsite manufacturing continues to grow. While the Offsite Construction (OSC) transition has brought positive changes to the industry, it also presents various challenges. Literature suggests that to address the challenges, advanced technologies such as Building Information Modeling (BIM) can be applied for effective mitigation. Nonetheless, the combined application of BIM and OSC is in its infancy and faces challenges in many countries. This study aims to investigate the factors influencing OSC and BIM integration, including challenges and strategies within the New Zealand construction industry.

This study explores which specific factors impact integration positively or negatively through a comprehensive literature review and confirmatory survey. Factor Analysis (FA) was used as the data analysis method, resulting in eight groups of underlying factors. Next, three Structural Equation Models (SEM) were developed and tested to analyze the impact of latent and observed variables on OSC and BIM integration.

Significant underlying factors affecting OSC and BIM integration were identified, and recommendations to enhance integration were provided. Specifically, the findings demonstrated that three underlying factors for challenges, two for strategies and three for integration were identified through EFA and confirmed by CFA. This step was followed by SEM, which employed three different path analysis models for integration variables. It clarified that not all variables have similar impacts on integration; some exhibit significant positive or negative effects, while others are not significant at all.

The identified challenges and strategies for OSC and BIM integration and their impact on integration factors can contribute to developing standardized integration guidelines and frameworks to assist stakeholders in focusing on their specific integration goals.

This paper reports the developments of a project cost control system (PCCS) for construction projects to (1) measure its current level of cost control maturity, (2) examine the relationships between elements within PCCS processes and (3) identify improvement areas.

This study adopts a mixed approach of descriptive analysis and partial least squares structural equation modelling (PLS-SEM) to measure the current maturity level of PCCS and evaluate the relationships between elements within PCSS to identify improvement areas. Further importance-performance matrix analysis (IPMA) of priority constructs was conducted to improve a target construct and identify the most important areas of specific actions at indicator levels. The results of IPMA revealed the contrast that has the greatest importance on the performance of others so that the recommendations can be made accordingly. Data collected in New Zealand were used to develop the research model.

This study develops structural and measurement models with the constructs including pre-control, in-control and post-control processes, enablers and their proposed interrelationships. Then, data from survey of 184 experienced project cost control team members reveal that post-control has the lowest maturity or weakest areas in the PCCS. Data analysis facilitated by PLS-SEM confirmed that all the constructs in the structural model have positive and significant relationships with each other and suggested that systematic cost analysis reports, communication, skills and experience, defining roles and responsibilities, and top management's support should be the highest priority for improving the PCCS in a more effective manner.

This study presents one of the earliest attempts to develop and test an integrated model that links sub-processes in PCCS and their enablers. Secondly, this research adds to the construction project management literature by empirically verifying the roles of enablers in enhancing maturity level of PCCS.