Abstract
The cause-and-effect diagram was not included in Seven Tools of TQM in Healthcare (2012), as it was considered a basic QC tool, frequently used without question, and not requiring detailed explanation. However, inappropriate diagrams have been reported across various fields, including healthcare. Due to the lack of systematic training materials, I developed internal content at Nerima General Hospital and conducted employee workshops. This led to training sessions at All Japan Hospital Association. Based on these efforts, we published Basics and Applications of Cause-and-Effect Diagrams in 2018 for educational use. Despite these activities, misuse persisted. In 2022, I proposed adding the cause-and-effect diagram as the “ eighth tool ” of healthcare TQM. Reflecting continued outcomes from training sessions, the second edition of Cause-and-Effect Diagrams was published in March 2025. This report outlines the theoretical background and practical development of cause-andeffect diagrams to improve their proper use in the healthcare field.
