Employee engagement in the United States has probably never enjoyed rock-star ratings. But Gallup's State of the American Workplace 2010-2012 report published an especially dismal statistic: 70 percent of American employees fail to work to their full potential.

Gallup defines an engaged employee as one who is passionate about her work, and feels a personal connection with her organization's mission. She works hard and earnestly to drive the organization forward.

Conversely, a "not-engaged" employee does her work mechanically, without putting energy or passion into it. According to Gallup, 52 percent of the entire workforce falls into this category. Another 18 percent of employees are "actively disengaged," meaning that they're unhappy at work and actively undermine their organizations' missions. This kind of worker not only is a drag on his organization, but on the entire U.S. economy—Gallup estimates that actively disengaged employees cost the United States $450 billion to $550 billion every year in lost productivity.

Gallup suggests that although employers are more aware of engagement today, there is still ground to close between knowing about it and doing something about it. Yet igniting employees' passion and commitment to their work doesn't have to be difficult.

The strategies Gallup identifies as sure to drive up engagement levels are simple and direct: Define engagement goals (and performance goals, for that matter) in realistic, everyday terms, ensure that managers connect personally with each employee, and take great care in selecting managers with the right interpersonal skills for the job.