According to New York Times, March 20 about Israel's Air Defense System, Iron Dome:
Israeli officials initially claimed success rates of up to 90 percent.
...
But a growing chorus of weapons experts in the United States and in Israel say their studies — based largely on analyses of hits and misses captured on video — suggest that Iron Dome destroyed no more than 40 percent of incoming warheads and perhaps far fewer.
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From such evidence, as well as from rocket and warhead basics, Mr. Lloyd estimates that the system succeeded 30 percent to 40 percent of the time in detonating enemy warheads.
Is the Iron Dome system effective 90% of the time?