The Latest (Almost) on Cell-Only Households

Today I was visited by Tim Veitengruber who had questions from a client about the likely impact of cell-only households on their satisfaction survey measurement.  Unfortunately, Tim’s timing is a little off. He needs to talk to his client on Friday.  The AAPOR Annual Conference starts on Thursday and there are well over a dozen papers in the program dealing with the issue of cell-only households.  As Clyde Tucker joked to me at last year’s conference, "The emergence of cell-only households is like a full employment act for survey methodologists."  I’m not sure what these papers will say, but Tim needs answers this week and here is what I told him:

1. I have not seen a new reliable estimate of cell-only households since last year and while the number no doubt has grown mostly people continue to cite 15 percent. 
2. The coverage problem is most severe among young adults, especially lower income young adults.  While the most recent study that I have seen shows that including cell phones in a survey does not change the overall results, there are potentially significant differences if you focus only on the younger cohort.  Put another way, any bias created by not including cell phones in a study is correctable with demographic weighting as long as you are not targeting younger adults or behaviors that might correlate with the likelihood of being a cell-only household.
3. The cost of a dual frame design that includes cell phones as well as landlines is significant.  In a test we just completed we found that a cell phone complete costs about four times that of a landline complete.  The refusal rate in the cell phone sample was two and a half times the landline rate, the incidence of non-working numbers twice that of the landline sample, and the number of no answers also twice that of landlines.

Of course, there might be some new results unveiled this weekend that challenge all of this, although I doubt it.  So we wait and watch.

In the meantime, AAPOR has just released a some guidance on the issues which was very thoughtfully done.  If you care about this issues it’s worth a read.