Great leaders make smart choices to address changing realities, new opportunities and potential risks. They recognized the danger of relying on habit or past practice for future success. No one should use a rear view mirror to guide an organization's future. Brilliant or Blunder offers a framework to enable leaders to collect, analyze and evaluate current circumstances before jumping into action. This book presents a dynamic results oriented template expanding the traditional models based on leadership style and competency. Critical thinking mastery successfully leverages new opportunities into sustainable and desired results. Thinking mastery can be quickly developed, since it does not depend on a high IQ, position or tenure. Brilliant or Blunder outlines how to expand mindset mastery using six buckets to collect data for wise decision making given current circumstances. Based on sixteen years of research, the leadership mindset checklist ensures that leaders make the right call at the right time to deliver the right results.