Every time we elect a new president in the United States, we watch his first hundred days in office closely. This has been the case ever since Franklin Delano Roosevelt's inauguration in 1933, amid the devastation of the Great Depression. FDR initiated a flurry of activity, enacting fifteen major laws to push the country out of its economic plight. He set a rather high bar, and we've judged subsequent presidents by it.
But it's not only presidents whose who face this "first hundred days" proving ground. When you become CEO—especially if you've never held the role before—you're going to be under quite a bit of scrutiny. In the opening stretch, employees, customers, and shareholders will form a sense of how you operate as a leader—and whether they will trust you and follow you.