This YouTube video introduces the theory of the Trust Equation:

What is the Trust Equation and the four areas of trustworthiness?

Psychologically, we have an intuitive feeling about whether we should trust someone or not. Whether that is a person we have just met or someone we have known or worked with for a while, it turns out that this feeling is based on some factors that can be measured. This is where the Trust Equation comes in.

The Trust Equation was developed by Charles Green, co-author of The Trusted Advisor, along with David Maister and Robert Galford. They explored the psychology of trust by looking at professional services and how people relate to one another. The result of this study was the Trust Equation.

The equation is actually a measure of trustworthiness, in other words, how much trust we are willing to invest in a person. In this context, to have trust between two parties, you need someone who is trusting and another person who is trustworthy. The equation involves credibility, reliability, intimacy and self-orientation.

For more information, follow the link to the full article:

How to Judge if Someone is Trustworthy Using the Trust Equation