Cell Phones May Double Your Survey Costs
These days most researchers agree that if you want to do a random sample phone survey of the U.S. population, you ought to include cell phones. More than one-quarter of the population do not have landline telephones at home. Those who do have landline telephones are less likely than ever to answer them, and less likely than ever to participate in surveys.
But it is not easy to include cell phones. The sampling protocols and the post-stratification weighting become more complicated. You need to account for a higher probability of cell phone owners being in your sample, because most of them also have landlines. You can’t use automated or predictive dialing to call cell phone numbers. You can’t target geography as well, because area codes and exchanges have become mobile. And people get mad at you if they have to pay for incoming calls, so you need to offer cash.
What’s the bottom line effect on costs for a survey that includes cell phones? A recent study sponsored by the American Association for Public Opinion Research (AAPOR) documents the following:
The cost of fieldwork for cell phone interviews is double if you don’t screen out those who also have landlines, and more than double (2.6 times higher) if you do screen them out.
Of course if you are surveying the whole population, only a portion of your sampling and interviews will be cell-phone based. Currently, we recommend that 20% to 40% of interviews be cell-based. But there are additional professional costs to remember as well, such as purchasing, managing, merging, weighting, and analyzing different types and sources of sample, and training interviewers to work with different sources and types of respondents.
There are still plenty of phone surveys being done that do not include cell-phones, and for many types of studies landline-only surveys produce information that is good enough for what needs to be learned. But it is getting increasingly difficult for these surveys to achieve true representation and surely their days numbered.
Feel free to give us a call if you need help figuring out the best approach for your research. We can advise you on the most cost-effective, feasible, and rigorous approaches to getting the data, stories, and level of understanding you need.
—Joe Hopper, Ph.D.