Some businesses believe that it is best to “under-promise and over-deliver.” For example, a business might believe that something can be delivered on Thursday, but the company will tell the customer that it will be ready on Friday—all the while trying to satisfy the customer on Wednesday. It’s believed that it’s better to satisfy the customer in a good way (by something unexpectedly early) rather than in a bad way (by something unexpectedly late).
 
“Underpromise and Overdeliver” was cited in print in a 1985 book by Gifford Pinchot III. “Entrepreneurs should ‘under-promise and over-deliver’” was cited in a July 1986 newspaper article about Pinchot’s advice to a company. “Under-promise, Over-deliver” was also cited in Thriving on Chaos: Handbook for a Management Revolution (1987), by bestselling business management author Tom Peters. Peters is often given credit for “underpromise and overdeliver,” but it does not appear that he used it before Pinchot.
 
Not everyone believes that “underpromise and overdeliver” is the best business strategy. Some believe that promises should be realistic (to match the competition). If a business underpromises and overdelivers on a consistent basis, then customers will continue to expect that to happen.
 
   
Wikipedia: Gifford Pinchot III
Gifford Pinchot III is an American entrepreneur, author and co-founder of the Bainbridge Graduate Institute. He is the grandson of the first Chief of the United States Forest Service and the 28th Governor of Pennsylvania, Gifford Pinchot, and is widely recognized for carrying on his grandfather’s work in conservationism.
 
In 1985 he wrote the best-selling book “Intrapreneuring” on the topic of Intrapreneurship; a revised edition, entitled “Intrapreneuring in Action” is currently published. The term Intrapreneurship is generally credited to him.
 
Google Books
Intrapreneuring:
Why you don’t have to leave the corporation to become an entrepreneur
By Gifford Pinchot
New York, NY: Harper & Row
1985
Pg. 190:
Underpromise and Overdeliver
Rather than promote the wonders of your project, do just the reverse: underpromise and overdeliver. Build slack into all your projections and promise just enough to get to your next stage of funding.
   
21 July 1986, Cumberland (MD) Times/News, “Translating Big ideas,” pg. 21, col. 1:
SAN DIEGO (AP)—Entrepreneurs should “under-promise and over-deliver,”  while transforming dreams into reality, advises a consultant on innovation.
 
People with a “big idea” should know how to translate it into a saleable product and then be able to move the concept through a corporate boardroom into the marketplace, Gifford Pinchot III recently told a seminar of Emhart officers.
 
Google Books
Thriving on Chaos:
Handbook for a Management Revolution
By Tom Peters
New York, NY: Knopf: Distributed by Random House
1987
Pg. 118:
Under-promise, Over-deliver

Google Books
The New Manager’s Survival Manual:
All the Skills You Need for Success
By Clay Carr
New York, NY: Wiley
1989
Pg. 34:
(In fact, he has a sign on his wall that says “Underpromise and Overdeliver” and every so often he lectures his workgroup on it.)
 
13 October 1990, The Stars and Stripes (Europe edition), “GM tackles import market with new Saturn models” (UPI), pg. 6, col. 2:
“Our philosophy is to underpromise and overdeliver.”
 
9 February 1993, Palm Beach (FL) Post, “bettman makes solid impression in solving NHL problems,” pg. 8C:
“It’s always better to under-promise and over-deliver.”
         
Fast Company
October 31, 1995 | 5:00 AM (November 1995 issue)
The Fad That Forgot People
One of reengineering’s creators explains the iron triangle that turned a modest idea into a destructive fad—and offers advice on how to avoid the next one.
By: Thomas H. Davenport
(...)
Finally, reengineering’s enduring lesson is that the bigger the hype the greater the chances of failure. Before reengineering became The Reengineering Revolution, innovators were experimenting with a variety of change practices. With the exaggerated promises and heightened expectations came faddishness and failure. The lesson: companies should underpromise and overdeliver. The time to trumpet change programs is after results are safely in the can.
 
FT Press
Rules of Work, The: The Unspoken Truth About Getting Ahead in Business
Rule 5 of Work: Underpromise and Overdeliver
By Richard Templar
Aug 19, 2005
If you can have it done by Wednesday, say you’ll have it done by Friday. Then, deliver it on Tuesday. That’s the key to the rule for success in this sample chapter.
 
WorkAwesome
Why You Shouldn’t Underpromise and Overdeliver
Peter North 15th June 2010
“Underpromise and overdeliver.”
 
Have you ever heard this brief bit of business philosophy at work? It has to do with consciously managing the expectations of your clients and customers. The idea is that you set a comfortable scope and timeline for your service, and then “wow” them by delivering the results ahead of time and under budget.
 
The question is: Is it a good way to build relationships with your customers?
 
While the short-term results of “underpromising and overdelivering” look great, your clients might come to always expect super-fast, super-cheap work from you.
 
Life’s Best Advice
“Underpromise and overdeliver”
Posted on August 3, 2010
From one of the best business minds ever … Tom Peters. I’m a huge fan of Tom Peters but I never have followed this advice. Not because I don’t trust or admire his judgement – but because I’m bored by the notion of “underpromising”.
 
The ”Underpromise and overdeliver” principle suggests it’s better not to promise something to your customer that you cannot keep than to under promise and to surprise your customer with good service.
 
Google Books
Book of Business Quotations
Edited by Bill Ridgers
Hoboken, NJ: John Wiley & Sons, Inc.
2012
Pg. 199:
Underpromise; overdeliver.
Tom Peters, management writer (1942–), quoted in the Chicago Tribune, June 1987