All passed an important test to see whether the chinstrap will hold in an accident. But two ran into problems in the impact test, which simulates what happens when a helmet hits various surfaces.
The two helmets that did poorly are adult helmets - the Nutcase Street Sport 8 Ball and the Bern Brighton Thin Shell EPS for women. However, if you have one of those helmets, Consumer Reports advises to continue wearing it until you can replace it because wearing any helmet is better than wearing no helmet at all.
Consumer Reports did find some good helmets to recommend - the $60 Specialized Echelon for adults and, for children, the $45 Bontrager Solstice Youth.
Consumer Reports cautions that no helmet will protect well unless it is worn properly. Make sure it's level on your head, with no more than one or two fingers-width above the brow. The straps should form a "V" under each ear with the buckle centered under the chin. When you open your mouth, the helmet should pull down.
It's a good idea to try on a bike helmet before you buy it. You want it to be comfortable, and it should fit snugly. You should be able to shake your head back and forth without the helmet moving, even before you strap it on.