Charles Green vs David Maister: Two Co-Authors of the Trust Equation and Their Different Emphases
Comparing Charles Green and David Maister, co-authors with Robert Galford of The Trusted Advisor: how their separate work on trust-based selling and on managing professional firms differs, and how to use both bodies of work.
Charles Green and David Maister share a book and an equation. They co-wrote The Trusted Advisor with Robert Galford, and the Trust Equation became one of the most used frameworks in professional services. Since then, each has pursued his own work. People compare them to see how one idea has been developed in two directions.
What is the core difference?
Maister writes about the professional and the firm. His concerns are how a professional service firm should be organized, what makes professionals excellent, and how partners should behave. The trust idea is one part of a larger view about professionalism and leadership.
Green writes about the practice of trust. His concerns are how an individual advisor or salesperson can earn trust through listening, vulnerability, and putting the client first. He has built a consultancy and body of tools around the equation.
One works at the level of the firm and its values. The other works at the level of the next conversation.
What did Maister write?
David Maister was a professor at Harvard Business School before becoming a consultant to professional firms. His books include Managing the Professional Service Firm (1993), True Professionalism (1997), Practice What You Preach (2001), and Strategy and the Fat Smoker (2008). The Trusted Advisor (2000) was written with Green and Galford.
His writing is direct and often critical of the habits of partners. He has written at length about client focus and the importance of firm leadership.
What did Green write?
Charles Green, a consultant and author, founded Trusted Advisor Associates and has written and spoken about trust for two decades. Trust-Based Selling (2006) applies the equation to sales. The Trusted Advisor Fieldbook (2012), with Andrea Howe, offers exercises and tools.
His approach emphasizes small, concrete behaviors, such as listening before advising, naming the unspoken, and reducing self-orientation. His organization sells training and certification built around these methods.
How do they compare?
| Dimension | Green | Maister |
|---|---|---|
| Focus | Practical application of trust to selling and advising | Management of professional firms and professionalism |
| Separate works | Trust-Based Selling (2006); The Trusted Advisor Fieldbook (2012) | Managing the Professional Service Firm (1993); True Professionalism (1997) |
| Joint work | The Trusted Advisor (2000), with Maister and Galford | Same |
| Audience | Individual advisors, sellers, and consultants | Firm leaders, partners, and professionals |
| Business model | Trusted Advisor Associates: training and certification | Books, and formerly a consulting practice |
| Typical question | How do I earn trust in this conversation? | How should a professional firm be run and led? |
| Style | Practical, tool-oriented | Direct, critical, managerial |
When does each one fit?
Green's work fits when you want concrete practices for building trust with a client or colleague: how to listen, how to raise difficult issues, and how to reduce your own agenda in a conversation. His tools help translate the idea into habits.
Maister's fits when you are thinking about the firm: how partners behave, what the firm rewards, and whether the culture supports the trust you want your professionals to build. His critical eye helps examine incentives.
For an individual, the two perspectives together show both what to do and what will support or undermine it.
What does this look like in practice?
A professional wants to become a trusted advisor to an important client. A Green-style plan identifies the next conversation, sets an aim of listening more than advising, names something the client may not want to say, and tracks whether the advisor's agenda is visible. It focuses on behavior.
A Maister-style review looks at the firm: does it reward the advisor for the client's long-term interest or for short-term billing, do partners collaborate or compete for credit, and does leadership model the behavior it asks of others? It focuses on conditions. An advisor in a firm that rewards self-interest will find trust hard to sustain.
"I want to become a trusted advisor to [client]. First, in Green's spirit, plan my next conversation: how I will listen, what unspoken issue I will name, and how I will keep my own agenda out of it. Then, in Maister's spirit, list what in my firm's incentives and culture supports or undermines trust, and one change I could argue for. Credit the Trust Equation to Maister, Green, and Galford in any notes."
Why it works: behavior builds trust and conditions determine whether it lasts.
Can you use both together?
Yes. They are co-authors, and their work is designed to fit together. The Trust Equation links their efforts, and later work extends it in different directions.
Check attributions. The Trust Equation is a joint product and should be credited as such.
"Our team's client habits are: [describe]. For each of credibility, reliability, intimacy, and self-orientation, tell me which of our habits raise or lower it, and which are firm-level issues in the manner of Maister and which are individual behaviors in the manner of Green. Suggest one change for each."
Why it works: separating firm-level and individual causes points to the right place to act.
For related comparisons, see Frances Frei vs David Maister.
Where to go next
Charles Green and David Maister both sit in the Consultant & Advisor category. For the originals, read The Trusted Advisor by Maister, Green, and Galford, Trust-Based Selling by Green, and Managing the Professional Service Firm by Maister. Green's organization sells training, so use the books to judge fit. To prepare questions for a sales call, Discovery Call Prep is a $79 tool built for it.
Frequently asked questions
Who developed the Trust Equation?
The Trust Equation was introduced in The Trusted Advisor (2000) by David Maister, Charles Green, and Robert Galford. Attribution to all three is accurate, and crediting Maister or Green alone leaves out the others. Both Maister and Green have developed the ideas in separate work since, so comparing their emphases is a way of seeing how a shared idea was extended.
What is the Trust Equation?
It states that trustworthiness equals credibility plus reliability plus intimacy, divided by self-orientation. Credibility concerns whether your words can be believed, reliability whether your actions match, intimacy whether people feel safe sharing with you, and self-orientation whether your attention is on yourself or on the other person. Raising the top or lowering the bottom increases trust. Treat it as a way of structuring reflection about your own behavior, not as a precise score.
What did Maister write separately?
Maister wrote Managing the Professional Service Firm (1993) and True Professionalism (1997), on how professional firms are organized and how professionals should behave, and Strategy and the Fat Smoker (2008), on the difficulty of acting on what we know we should do. His focus is firm management and professional character. Maister's books are widely read by partners and managers in law, accounting, consulting, and architecture firms.
What did Green write separately?
Green founded Trusted Advisor Associates and wrote Trust-Based Selling (2006) and, with Andrea Howe, The Trusted Advisor Fieldbook (2012), which turn the equation into practices for selling and relationship building. He also writes and speaks regularly on trust. His focus is practical application for individual advisors and sellers. His organization also offers workshops, so the books are a practical way to judge the approach before paying for training.
Do they disagree about anything?
There is no documented public disagreement. Their work is complementary, with Maister more focused on firms and professional behavior and Green on the day-to-day mechanics of building trust. Differences arise mainly from emphasis and audience. Reading both shows the idea from the point of view of the firm and the individual. Readers who want both sides should read The Trusted Advisor first and then choose a separate book by emphasis.
Can AI help me apply the equation?
It can draft questions to assess each component, help plan a trust-building conversation, and review a message for self-orientation. It cannot judge how another person feels. Use it for preparation and then ask the person. For example, ask it to draft questions about each of the four components for a client, or to rewrite a message so that it focuses on the client's needs. Verify attributions against the books.
Written by Gareth Hoyle. Last updated 8 October 2026. Part of the authority.md guides library.
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