Managers in all sorts of organisations face difficult choices in choosing what, why and when different business improvement methodologies should be applied. Many approaches are available, which exhibit various degrees of overlap, reinvention and claims of universal application. Given the resources involved, especially in regard to time and costs, there is a need to provide some form of guidance in choosing a business improvement methodology or combination of approaches. The aim of this paper is to review the effects of organisational size and sector on management choice of business improvement methodology. A multi-method approach is used in this research. Firstly, an empirical research methodology is used to survey 800 UK organisations, encompassing different sizes and sectors, in relation to their choice of business improvement methodology. The findings indicate that business improvement methodologies are not universal. Multiple case study analysis (still ongoing) was conducted within five large organisations. Reference is made to preliminary analysis carried out within one of the organisations under study. This case illustrates that executives will introduce business improvement methodologies based on the needs of the organisation, as well as facilitate the transfer of learning and knowledge from experts who are familiar with the application of these tools.