Great read out of Psychology Today about the difference between a Vision statement and a Mission statement and why having clearly defined mission and vision is important. (Can you say Culture?)
"A study by Bain and Company indicated that organizations that have clearly defined Vision and Mission statements that are aligned with a strategic plan, outperform those who do not." Reason enough?
How about hiring is easier when you can articulate a clear vision and mission to candidates?
"As Jack Welch, Chairman, General Electric said, "Good business leaders create a vision, articulate the vision, passionately own the vision, and relentlessly drive it to completion.""