When I ask entrepreneurs and small business owners, it is not unusual for not having any marketing plan. I once read that Sir Richard Branson never had any marketing plan when he started the 1st Virgin business many years ago. In fact in one study of entrepreneurship (I couldn't recall the name of the study) was that as much as 50% of entrepreneurs and business owners don't have a business plan and marketing plan when they first started the business.
Performance measurement: constitutes the last but not the less important stage of the marketing plan, since we can achieve only what we can measure. In order to measure the performances achieved through the marketing plan, we need to constantly monitor each previous stage of the plan.