[Navy Patriot]

The Doolittle Raid was a brilliant Publicity Attack that significantly Raised Morale throughout the Entire Pacific Theater and North America.

America could Bomb the Japanese Home Islands anytime they wished.

[Tallguy]

The raid did have some very real effects because it lead to a mis-allocation of IJN surface vessels to guard the approach used by the Enterprise-Hornet battle group to prevent a repetition of the Doolittle Raid. There is also some evidence that it sparked Japanese planning for the seizure of Midway Island — and we know how that went.