Are mission statements still relevant?

I'm writing an advisory for a company that's already running for over 4 years. One of the things that came up is that they don't have any written mission statement. What is the modern opinion on this subject? The subject being: is their use still of significant importance to a company or not?

I read somewhere that leading by example is of more practical use than formulating a mission statement. So now I am searching for some renowned sources to quote on the subject.

TL;DR - mission statements still exist, but many choose to represent this as a manifesto.

Example - from google: mission statement

Google’s mission is to organize the world’s information and make it
universally accessible and useful.

vs their philosophy: 10 things we know to be true.

• Focus on the user and all else will follow.
• It’s best to do one thing really, really well.
• Fast is better than slow.
• Democracy on the web works.
• You don’t need to be at your desk to need an answer.
• You can make money without doing evil.
• There’s always more information out there.
• The need for information crosses all borders.
• Great just isn’t good enough.

We all have heard the phrase "do no evil" and "google" but rarely hear about their mission statement.

Another example: "philosophy" statement / mission statement: SEOmoz's TAGFREE In the internet space, many companies point towards "beliefs" more than the mission statement.

One author that comes to mind is Guy Kawasaki; who has published several relevant books on entrepreneurship. I can't fully remember which of his books deals most with mission statements -- I think it is "The Art of Start".

He is dead set against the standard corporate motto. This I like. Instead, he proposes a "mantra". The gist of his proposal goes like this:

1. Make meaning. (Loosely, find a major pain point which good people will be passionate about solving.)
2. Make Mantra. (Loosely, create a super-simple chant / mantra people can rally around.)

You can find a micro-explanation of this here, but you should really read the more comprehensive version in the book.

However, the truly authoritative writer on mission statements was the Dilbert Mission Statement Generator. Sadly it no longer exists, but a quick Googling brings back some examples of its writings:

• “Our challenge is to assertively administrate timely resources and authoritatively integrate enterprise-wide products while promoting personal employee growth.”
• "Our challenge is to assertively network economically sound methods of empowerment so that we may continually negotiate performance-based infrastructures."
• "Our mission is to continue to conveniently supply seven-habits-conforming data such that we may continue to authoritatively integrate value-added catalysts for change while promoting personal employee growth"

It's a great question, that so many companies get wrong.

Peter Drucker, deceased legendary management author since the '40s, has the most notable insights on the subject:

A mission statement has to be operational, otherwise it's just good
intentions. A mission statement has to focus on what the institution
really tries to do and then do it so that everybody in the
organization can say, This is my contribution to the goal.

So you need three things: opportunities, competence, and commitment.
Every mission statement, believe me, has to reflect all three or it
will fall down on what is its ultimate goal, its ultimate purpose and
final test. It will not mobilize the human resources of the
organization for getting the right things done.

"It's our mission to give assurance to the afflicted" --hospital
emergency room

"To help girls grow into proud, self-confident, and self-respecting
young women" --Girl Scouts

"Make citizens out of the rejected" --Salvation Army

"Make gentlemen out of savages." --Arnold of Rugby, the greatest
English educator of the nineteenth century, who created the english
public school.

"Be the informed and responsible buyer for the American Family" --
Sears

*Drucker advocates, "an organization's mission statement should fit on a T-shirt". Also, It's funny to hear Guy Kawasaki talk about the common procedure for creating a common mission statement. 'A company takes it's leadership to a retreat where they do trust falls and ropes courses with people they don't like, and develop a mission statement based around everyone agreeing to broad watered down nice sounding statements.'

Ahh, the elusive mission statement.

I come out of an academic background that loves mission statements. It is called Organizational Development. OD Consultants believe that a company must have a clear mission statement. We could discuss for a long time how this emerged in the context of organization developmental with roots in Military efficiency and effectiveness -- but then we would be continuing to provide this topic far more time that it deserves.

So I am not a 'great published writer" with a book you can quote and provide to your client -- but I will tell you this from personal experience as an orgnaizational development consultant:

There is absolutely no correlation between coherent mission statement and success. And if (when) I am ever wealthy (again) I will personnaly refund all my clients I every accepted money from in the bullshit exercise of developing either a vision or mission statement.

Until then a simply sorry will have to do.

I am sorry to have wasted your time and organizational resources. I wish we would have focused on understanding your market, your customers, the core value proposition you offered, how you were going to deliver that propsition, and provide a positive return to your owners and stakeholders.

If you must try this: To deliver real value to our customers in manner that builds value for our owners. You can polish it a little to personalize it if you want.

Then, get back to work.