🧵 Lots of people like math and read that Israel’s Iron Dome had a 90% success rate at interceptions. Then they compare the nunber to the overall rockets fired in the recent war, some 4,300, and do math. But that’s not the number they should use.
Example May 16, 2021 “IDF: As of 19:00, approximately 3,100 rockets have been fired from the Gaza Strip at Israeli territory, of which approximately 450 failed launches fell in the Gaza Strip.
The Iron Dome Air Defense System has intercepted approximately 1210 rockets.”
The Iron Dome Air Defense System has intercepted approximately 1210 rockets.”
If you do the math you’ll think that there is something missing. Indeed, the 1,210 nunber is 90% of the rockets that the system attempted to intercept” DO NOT use the overall number of rockets. Most fall in open space or even fail to launch.
The system uses algorithms. It’s not designed to intercept every rocket. That would make it a dumb system actually. Why intercept everything. It intercepts priority threats. We don’t know the X and other variables of the algorithm that decides that.
What we do know is that before May 10,2021 there were 2,500 interceptions since 2011 out of probably 9,000+ rockets (4,000 in 2014, 1,500 in 2012, 2,600 in 2018-2019 etc)...example 
What we do know when it comes to numbers is that around 1/3 are attempted interceptions and the success of that is 90%. That’s the math.
When I wrote “dumb system” I mean a dumb system would intercept everything and be a huge waste. You don’t intercept everything. You intercept what matters the most and then down the list.
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