If by "harder" you mean is it more difficult to be accurate with a longbow than a compound, the answer has to be yes. Just look at the relative scores posted in most any competition and you'll find the compound scores are higher. The lighter holding weight, heavier mass, and use of sights and especiallymechanical releases with most compounds all contribute to higher scores and greater accuracy. The average individual with about two weeks of concentrated practice can become competent enough with a compound to hunt. The same individual would probably require months of practice with a longbow to achieve the same level of accuracy.