Why do workers take a chance and work from height without any safety protection? Is it because of their age, inexperience or lack of training? Is it to do with their risk perception or desire for risk taking and thrill seeking? Is it bad management style, poor safety culture or a substandard design? Does this happen everywhere around the globe or is it just one particular culture? To help us understand why there are different behavioural responses to hazards (e.g. working at height) in construction, we must first understand the factors that have affected that individual’s decision-making. This paper presents early investigations taking place on a £1.6B project in the UK involving construction workers from many different backgrounds and nationalities. Through a process of literature exploration, a safety climate survey and focus group discussions, factors have been identified and explored to consider how they impact behaviours. The results suggest that time pressure, training, experience, risk perception, safety culture, culture and management are the factors most likely to be influencing behavioural responses of individuals. Time pressure is perhaps the most important factor as it was often regarded as having the greatest influence by the focus group. Survey results revealed 31% of 475 participants thought that alcohol and drugs were 'always' a factor in accidents, and hence this factor has somewhat surprisingly been identified as having a fairly significant influence. These factors will be further explored in future work using an ethnographic approach, which will yield significant insight from fine-grained, observational analysis on the project