This simple exercise can help you achieve your goals in 2016

Last December, faced with the realization that I'd neglected a number of friendships while tending to my career and a new romantic relationship, I resolved to do a better job of keeping in touch with friends in 2015.

I failed. Miserably. In the past 12 months, I've been berated by more than one close friend for failing to return phone calls, forgetting birthdays, and flaking on dinner plans.

Where did I go wrong? And why do more than eight in 10 well-intentioned people fail to achieve their New Year's resolutions?

Part of the problem, even when we have a specific action plan in place, is that we don't fully appreciate the motivation behind the resolution.

One way to solve it? Craft a personal mission statement.

The idea of a personal mission statement - similar to a company mission statement, but just for you - appeared in Stephen Covey's bestselling book "The 7 Habits of Highly Effective People," originally published in 1989.

The second habit outlined in the book is to "begin with the end in mind." Covey wrote: "The most effective way I know to Begin with the End in Mind is to develop a personal mission statement or philosophy or creed. It focuses on what you want to be (character) and to do (contributions and achievements) and on the values or principles upon which being and doing are based."

Compared to resolutions, personal mission statements may be more effective in helping you achieve your goals.

As Jack Groppel, Ph.D., cofounder of the Johnson & Johnson Human Performance Institute, told The New York Times: "A resolution is a well-intended action plan, but because a person hasn't really connected to the 'why' behind it, the old way of life, the chaos, comes back into play and they can't really sustain it."