Leadership exists as a relationship between people who want to lead and people who decide to follow them, and people follow willingly only a leader they find credible. Over three decades the Characteristics of Admired Leaders survey (twenty attributes, respondents choosing seven) has placed four qualities consistently above the rest across countries, functions and age groups: honest, competent, inspiring and forward-looking; the first three correspond to the trustworthiness, expertise and dynamism of source credibility, and forward-looking is what distinguishes a leader. The authors state two laws: people who do not believe the messenger will not believe the message, and credibility is shown behaviourally through keeping one's word in action (the authors' DWYSYWD acronym), which has a say element (being clear about beliefs) and a do element (acting on them). High credibility in the immediate manager goes with pride, team spirit, values alignment, commitment and ownership; low credibility with working only under watch, money as the main motive, private criticism and readiness to leave.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.