Why do you mean by effective? accurate?
They are very accurate compared to carpet bombing... or unguided bombs who depend on the skills of the pilots/gunners...
But modern missiles are very accurate when the command uses high tech missiles. They have lasers to guide their missiles, GPS localization and tons of other high tech toys...
But it's the intel you have to question... and maybe the firepower to have effective strikes on the enemy without pissing off the whole neighborhood...