In the old days (decades ago), phone surveys had limited utility because many people had no phone service in their homes. When that changed, phone surveys became ubiquitous because they allowed researchers better control over the process. Data quality improved. Now increasing numbers of people have moved to cell phones only, which has been a significant challenge for the survey industry. The numbers are staggering:
The number of people without home access to landline telephones is increasing.
Almost half of adults under age 30 live in a household with only wireless telephone service.
