http://www.healthcaredive.com/news/uwe-reinhardt-adverse-risk-selection-crippling-obamacare/425182/

• The ACA has failed to attract enough younger, healthier people to the public insurance exchanges, causing Aetna and other private insurers to exit the market rather than shoulder the costs of sicker people, according to Princeton economist Uwe Reinhardt.
• To deal with adverse risk selection — where sicker-than-average individuals buy insurance while younger, healthier ones don’t — some payers plan to raise premiums more than 25% in 2017.
• That will lead even more young, healthy individuals to forego obtaining ACA coverage, creating even greater adverse risk selection, Reinhardt says.