An update on a previous post.
Statistics New Zealand recently released results from the Household Use of Information and Communication Technology survey. This is a high quality survey of about 15,000 private households and about 30,000 individuals each quarter. Surveys are carried mostly face-to-face and some are carried our via telephone.
Results show that 87% of households have a landline telephone (sampling error on this result is +/- .94 percentage points).
If we assume that around 2% of households do not have a landline telephone or a cell phone, this would mean that around 11% of households are ‘cell phone only households’. I think it was probably around 6% in 2006, so this is an increase. In my view 11% is too small a percentage to warrant including cellphone only households in telephone surveys – results for that 11% of households would need to be dramatically different from other households for this proportion to have much of an impact on a survey estimate (related post here).
Also, I’m not sure of the proportion of individuals who have a landline phone, which is useful when estimating non-coverage of landline telephone surveys. You could pay for a custom order from Stats NZ, but it probably makes more sense to wait for the Census results.
Also interesting, 80% of households now have internet access of some kind (sampling error of +/- .98 percentage points), up from 75% in 2009. This is a bit lower that I had assumed.