Reports on the results of a survey assessing the current level of use and perceived importance of improvement tools in the construction industry, together with the impact of the ISO 9001 quality system. More than 30 improvement tools were identified and categorized. The results showed that, in terms of use, quality control, performance measures and technology tools are common practice in the industry. A similar set of tools and techniques were perceived as highly important. A comparison of the mean use and mean perceived importance for each group of techniques revealed significant differences in tools that help to assess customer needs, those aimed at programming, and those used for performance measurement. So far as ISO 9001 is concerned, the survey showed that certified companies make more use of, and place higher levels of importance on, most of the groups of tools studied, than non-certified companies.