The stigma of asking for or being assigned an executive coach is vanishing quickly. The growth of the industry tells us so. In the U.S. alone, $1 billion was spent on business, personal and relationship coaches last year, according to IbisWorld, up about 20% from five years earlier. And the number of business coaches worldwide has zoomed more than 60% since 2007, according to one coaching association. But while executive coaches have improved the performance of many already-good managers and sanded the rough edges off many less effective ones, they aren’t a miracle cure. In fact, we have seen many companies waste considerable sums by assigning coaches to managers who just aren’t ready to be coached, no matter how effective the coaches may be.