One thing that virtually everyone seems to believe about survey research is that a bigger sample is better: a sample of 500 respondents is better than 100, and 1000 is better still. And best of all is a census where, technically, the margin of error is reduced to zero.
However, the truth of the research adage about bigger sample sizes holds if, and only if, there is no bias. And the probability of zero bias is rare.
Researchers know this – but the media and the general public do not. The press and their audiences fixate on the number of respondents in research. To overcome this problem, we need to talk about bias.
When the Census 2016 online form was inaccessible for more than 48 hours from 7.30pm on census night (August 9), it created a media flurry. However, when the ABS reported that more than 96 per cent of households had completed the census by the closing date (September 23), many concluded that the problem was resolved.
However, the problem of bias remains, and this is not necessarily resolved with a high response rate. The real #censusfail is less a data collection glitch and more the threat it has posed to data quality.