Duty-based ethics are ethics that revolve around specific higher principles. To be effective, they need to be universal and hold respect for others in high esteem. Examples of these ethics are everywhere, including the real world and in the workplace.
When you make a decision, you need to ask yourself who you owe a duty to and which is more important. So, if your sister asks you to steal something for her, you owe a duty to her in that she is your sister, but you also owe an equal duty to the person you are stealing from. Duty-based ethics are the assessment of whom you owe a greater duty to.
Assume your colleague asks you to lie to your boss. Your colleague wants you to tell your boss he is out on a sales call when in reality he is having a wet lunch in a bar. You need to assess who you owe a greater duty to—your boss, who pays your paycheck and has always treated you well, or your colleague, whose friendship is valuable to you.
Real World Example
Assume that at the end of the day, you go shopping on your way home. In the parking lot, you bump into someone else's car. Nobody sees. Now, you need to assess your duties—do you owe a greater duty to yourself or the other person? Duty-based ethics promote respect for other people, so in this case you need to leave a note in order to stay within duty-based ethics.