Abstract
Purpose
The causal relationships between factors related to building information modelling (BIM) adoption in the Thai architectural and engineering design industry are presented. A model is proposed to explain and forecast the adoption behaviours in the industry. This paper aims to define and compare policies for the adoption of BIM using a company case study.

Design/methodology/approach
The system dynamics (SD) approach was used. Four companies were selected as case studies for formulating a causal loop diagram. One of the companies was chosen for collecting the quantitative data for the SD model simulation during a ten-month study period. Tests of model validation were conducted for confirmation of, and confidence in, the model.

Findings
An SD model was formulated for studying BIM adoption. Four policies of BIM adoption were defined to compare with the normal operating business for the company and used as the case study. The quantitative outputs of the SD model revealed that BIM training was the best choice to optimise company performance.

Research limitations/implications
The case studies comprised architectural and engineering design companies in Thailand; therefore, the findings may not be generalisable to other Thai construction organisations or to other countries.

Practical implications
The methodology and findings can be used as guidelines for other organisations or countries that are considering BIM adoption to improve their operations.

Originality/value
The paper highlights the optimum policy for BIM adoption to achieve efficient and effective implementation.