This mode may allow you to reach the largest number of people, as one U.S.-based study found about 99% of people ages 18 to 49 have telephone access, compared to 73% having internet access (Pew Research Center, 2018). As such, the telephone allows you to employ probability sampling with relative ease, and is generally used with those methods rather than convenience methods like snowball sampling.
- Several technologies such as random digit dialing (RDD), computer-assisted telephone interview (CATI), and interactive voice response (IVR) allow you to take a simple random sample based on a database of phone numbers (Mahmutovic, 2020). However, these tend to cost money and require you to have a sampling frame in the first place, which means you would need to have a list of phone numbers to draw from. Of course, you may also perform your phone survey manually by creating your own list of numbers and designing a systematic way to take a random sample yourself.
- You may also use the aforementioned technologies for stratified sampling, but you need to have access to enough information about your sample population ahead of time in order to stratify it appropriately.
