Phone surveys were once the standard method for random-sample data collection. In New Zealand and many comparable markets, however, they have become increasingly unreliable and cost-prohibitive relative to current alternatives.
The key limitations are:
Sampling bias: mobile numbers are generally private and not publicly listed, making truly random sampling difficult. Landline use has declined significantly and is now concentrated among older households, meaning landline-based samples no longer represent the general population.
Low response rates: a large proportion of respondents do not answer calls from unknown numbers. Certain demographic groups, particularly younger adults and those in employment, are especially difficult to reach by phone, introducing further bias.
Cost: interviewer time and the need for multiple call attempts make phone surveys comparatively expensive per completed response.
Our Recommendation
In most cases, we recommend modern approaches: online survey panels; address-based invitations, or mixed-method designs, which typically yield larger, more representative samples at lower cost. Research also indicates that many respondents prefer completing surveys online at a time of their choosing, which can improve data quality and consistency.
When phone surveys have to be used
There are circumstances in which phone surveys remain the most suitable approach, for example, when replicating a prior study to ensure methodological consistency, or when the target population is best reached by phone (such as a defined business or interest community). In such cases, we are well placed to deliver a robust phone survey programme tailored to your specific objectives.