Iran's military strength has been weakened, but strike effectiveness has increased. It is estimated that up to a quarter of the missiles successfully breach defenses.

The United States and Israel’s intensive airstrikes lasting over three weeks have severely weakened Tehran’s military capabilities, but weapons remaining in Iran’s massive missile arsenal are being used more efficiently from bases in its eastern, hard-to-reach regions.

The latest example is the weekend attacks on Israel, which injured more than 100 people. Decker Eveleth, a research analyst at CNA Corp., a Washington-based nonprofit research and analysis organization, said the targets included Dimona — the site of Israel’s main nuclear research facility. The strikes likely used the “Khoramshahr” missile, which ranks high in range and payload within Iran’s stockpile.

The U.S. and Israel estimate they have destroyed about two-thirds of Iran’s missile launch sites. U.S. Secretary of Defense Lloyd Austin said Iran’s offensive capabilities have been reduced by 90%. Nevertheless, Tehran continues to target Gulf region sites, having launched over 1,200 ballistic missiles and at least 3,300 Shahid cruise missiles so far.

Kelly Grieco, a senior researcher at the Stimson Center, said that analysis of open-source strike data, including videos, images, and announcements, appears to show that since around March 10, the effectiveness of these attacks has significantly increased, with up to a quarter of the missiles successfully penetrating defenses. However, she cautioned that as more accurate information becomes available, this assessment could change.

She said, “Iran, whose strength has been diminished, has reduced the number of missiles and drones launched, but they are more precise, targeting is more cautious and fixed, making them more effective at imposing costs. In terms of penetration attempts, the trend is moving in the wrong direction.”