Construction firms operate within a business environment characterized by uncertainty and a lack of predictability, increasing the complexity of strategic decision-making. Construction contractor firms' strategic response to environmental turbulence is appropriately documented but evidence regarding Construction Professional Service Firms (CPSF'S) remains scarce. CPSF's are characteristically different from contractor organizations due to the intangibility of services and high knowledge intensity. The purpose of the study is to ascertain the impact of environmental turbulence on strategic decision-making process characteristics in CPSF's, specifically Irish Quantity Surveying (QS) practices. Using a mixed-methods research strategy, data collected over two dissimilar stages on the economic cycle is presented. A comparative analysis over time exposes the varied impact of environmental turbulence on strategy process characteristics, however, a notable shift in the strategic choice is evident. An emergent approach to strategizing coupled with a move from written strategic plans is evident, while competitor analysis remains superficial. A taxonomy of the strategic decision-making process is derived from the empirical data which uniquely highlights the role of path dependence for CPSFs. The paper provides theoretical advancement in the discipline of CPSF strategy and also identifies a crucial component for consideration in driving transformational change required across the sector.