JUDY WOODRUFF:

Now to the second part of our look at the Affordable Care Act and health insurance coverage, as year three gets under way.

This weekend marks the beginning of open enrollment in the health exchanges, and we're looking at some of the questions about costs and coverage. One development this fall that's turning into a concern for some consumers, a series of collapses of an alternative to traditional insurance plans known as co-ops.

Nearly a half of them, which were created through the Affordable Care Act, are now shutting down.

I sat down to discuss this all yesterday with Mary Agnes Carey of Kaiser Health News.

And Mary Agnes Carey is with us again.

So, welcome back.