I work with clients every year on vision, mission, core values and culture challenges. When we get to articulating core values, executives often defer to a standard list of behaviors like Integrity, Accountability, Responsiveness, Empowerment, etc. But this random list doesn't do anything for anybody.
Enron's core values were Communication, Respect, Integrity and Excellence. Most would agree that these values were anything but core to the company.
The culture was corrupt. And that's where I find executives get confused. Your core values emerge from the culture. They don't drive it.
If your culture is dysfunctional, it doesn't matter how many core values you list or how you word them. If the leadership doesn't demonstrate the kinds of behaviors you want, TELLING your employees how to act will fall on deaf ears.
Ralph Waldo Emerson put it this way: “What you do speaks so loudly I cannot hear what you are saying”
So, no, core values don't matter. Core behaviors do.
If you want to change a company, or help guide an organization to a positive new future, focus on the behaviors. Start at the top and cascade down. Once the leaders get it right you can consider making posters and t-shirts. Until then, no. You're just asking for trouble.