More on the cost of interviewing cell phones

Pew has just released a new study that confirms some of our own experience on the cost of interviewing respondents on cell phones.  Overall the report is about the impact of including cell phones in pre-election polls during the last presidential cycle, but at the end of the report they go into some "practical considerations" that are very interesting:

• Contact rates, cooperation rates, and response rates were nearly identical between landlines and cell phones.
• The eligibility rate (a.k.a incidence) was only 55 percent for cell phones compared to 87 percent for landlines.  The difference was due mostly to reaching a large number of cell phone users under the age of 18.
• On average, cell phone interviews were about two and a half times as expensive as landline interviews.  They divide that cost into four buckets: (1) 30 percent due to additional screening; (2) 30 percent for a $10 reimbursement; (3) 20 percent for manual dialing; and (4) 20 percent for additional labor for tracking, management, etc.

There also is commentary on the likelihood of people who are currently cell phone mostly transitioning to cell phone only, and it's not especially encouraging for the future of telephone research.

To the above I should add there there is a post on  Research-Live.com  that reports the finding as four and a half times expensive, atlhough the referenced Pew report seems to say two and a half.  I'm not sure how to reconcile.