Since 2005, Hamas and other Gaza militants have fired over 12,000 rockets at Israel. They caused at least ten deaths, over 1,100 injuries, and over $50 million in property damage. The Israeli Defense Forces (IDF) responded with three military operations against Gaza. Their stated goal was to protect Israeli civilians from the rockets.

However, critics have argued the collateral destruction and civilian casualties in Gaza were out of proportion to Israel’s own losses. Some questioned the operations’ legal and ethical justifications. The United Nations, International Criminal Court, and Amnesty International all opened investigations. The controversy also complicated the country’s international relations.

HOW PRODUCTIVE WERE ISRAELI OPERATIONS RELATIVE TO THEIR GOALS? WERE THEY EFFECTIVE AND EFFICIENT AT PROTECTING ISRAELIS FROM ROCKETS?

All those issues are important, but they overlook a key underlying question. How productive were the operations relative to their goals? Leaving aside their many secondary effects, were they effective and efficient at protecting Israelis from rockets?

Rocket data summary from "The Effectiveness of Rocket Attacks and Defenses in Israel" (via the author)

I have explored this issue in a study of Israeli rocket countermeasures covering Operations Cast Lead in 2008-2009, Pillar of Defense in 2012, and Protective Edge in 2014. The research estimated the operations’ effects, benefits, and costs. With limited data available, the estimates are rough but nonetheless informative.

VARYING DIRECT IMPACT

All three operations began with airstrikes; Cast Lead and Protective Edge followed these with ground offensives. While the airstrikes destroyed rockets and likely disrupted some rocket launches, my analysis shows they did not significantly reduce the daily rates of fire during any operation. The Gaza militants maintained their average fire rates, presumably by protecting or replacing their launch crews.

The daily fire rates during airstrike periods were also twice as consistent during Protective Edge relative to the earlier operations. The militants apparently had improved their ability to sustain operations under fire, perhaps thanks to their tunnel network.

ROCKET FIRE RATES DID DECREASE SIGNIFICANTLY AFTER GROUND FORCES ADVANCED DURING CAST LEAD AND PROTECTIVE EDGE. BUT THESE OPERATIONS WITH GROUND ASSAULTS INCURRED MUCH GREATER EXPENSES PLUS MILITARY CASUALTIES.

Rocket fire rates did decrease significantly after ground forces advanced during Cast Lead and Protective Edge. Controlling the ground in Gaza helped the IDF control the air over Israel.

DECLINING CIVILIAN BENEFITS

By destroying rockets preemptively, the IDF prevented them from harming Israeli civilians. For example, Cast Lead’s twenty-three-day air-land offensive claimed 1,200 destroyed rockets. If those had launched, they could have potentially increased civilian casualties by some 194 percent. That implies the rocket destructions prevented roughly six deaths and 274 injuries, or 280 casualties in total.

Pillar of Defense destroyed 980 rockets but only kept civilian losses from being 72 percent higher, avoiding four deaths and 173 injuries. The smaller impact follows from the operation lasting just eight days and lacking ground assaults. Israel’s civil defense expansions and Iron Dome interceptor deployments also contributed to the reduced casualty prevention.

Protective Edge’s impact was surprisingly modest, given its forty-two days of fighting and its intensive ground assaults. It prevented rocket casualties from being 101 percent higher, thereby avoiding just two deaths and eighty-four injuries. The number of rocket destructions exceeded 3,000, more than the previous two operations combined. However, the value of those destructions dropped due to Israel’s other countermeasures. Increasingly influential Iron Dome interceptors meant that just eight percent of rockets evaded interception and hit valuable targets. Improving civil defenses meant fewer such hits caught victims unsheltered.

HIGH MILITARY COSTS

Pillar of Defense was the least expensive operation, thanks to its brief duration and air-only nature. Dividing the IDF’s marginal cost by the number of rockets destroyed indicates an average cost of $290K per rocket eliminated. Alternatively, dividing by the total number of avoided dead and wounded implies a price of $1.6 million per civilian casualty prevented.

Operations with ground assaults incurred greater expenses plus military casualties. Cast Lead averaged $870K per destroyed rocket. Its price per civilian casualty prevented was $3 million plus 0.2 IDF casualties.

Protective Edge’s cost per destroyed rocket was $560K, midway between the other two. Unfortunately, the operation incurred far more military casualties than the civilian ones it prevented. Its price per civilian casualty avoided soared to $19 million plus 4.7 military casualties.

OTHER CONSIDERATIONS

The rough pricing above simplistically assumes rocket loss prevention was the operations’ only goal. Factoring other missions into this analysis would reduce the expense attributable to anti-rocket efforts. For example, if tunnel destruction unrelated to rockets generated at least eighty percent of the IDF casualties during Protective Edge, then the civilian casualties prevented begin outnumbering the military ones suffered. However, the price estimates also ignore the IDF’s capital and fixed expenses. Including those would increase the prorated estimates.

The calculations similarly ignore any deterrence benefits because they seemed minimal during the 2005-2014 period. In what the IDF informally called “mowing the grass,” one operation followed another every few years, with hundreds of rockets fired in between. Since 2014, Hamas has seemed deterred from firing rockets, though not from building them. The potential benefits of any limited deterrence would need to be set against the ongoing costs of the IDF deterrent force.

This discussion also ignores Israel’s indirect economic losses because of rocket fire. For example, during Protective Edge the country’s economy lost about $1 billion, or $24 million per combat day.

PROPORTIONALITY VERSUS PRODUCTIVITY

These results suggest that the military operations have become less effective and less efficient at preventing civilian casualties. The IDF seems good at destroying rockets; however, such preemptive strikes matter less because Israel’s civil defenses and interceptors have gotten better. Airstrikes by themselves reduce the rocket stockpiles but not the fire rates. Ground assaults do suppress rocket fire but also boost costs.

How Israel’s Iron Dome Actually Works (via Bloomberg)