Stats NZ is confident it can remove duplicate responses to the census. David Williams reports.
The good people of Palmerston North and Christchurch alerted the media last week they’d been sent two census letters in the mail with different access codes.
“I wouldn’t know whether to use the first one or the second one,” Cynthia Cooper, of the Manawatū city, told Newshub.
Confusion might have arisen but, it was reported, Stats NZ cleared the air.
Households could use either the new access code or the original, Stats NZ said – “both are valid and private to their address”.
READ MORE: * Trust in census a big issue, survey suggests * Census call to minister this weekend
As it turns out the second letter, a “pre-census reminder”, was strikingly common: it has been sent to 1.4 million households. One recipient was Simon Watts, the MP for North Shore, who’s the National Party’s statistics spokesperson.
“The most concerning aspect of this is that you seem to be able to submit twice, using both codes, meaning there may be double-ups in the dataset,” Watts tells Newsroom.
“This could have serious implications for the integrity of the data that’s collected, the minister and Stats NZ need to tell us how many people have received these double-ups and provide certainty that someone couldn’t enter or submit their data twice.”
Stats NZ confirmed not only could a person submit twice, it’s not even an offence to do so.
“If someone logs onto our census website with a different access code, after they have already completed the census, they will be able to do the census again,” says Simon Mason, the deputy government statistician and deputy chief executive of census and collection operations.
“For privacy reasons, access codes are not linked to previous responses.”
“We encourage the public to only complete the census once.” – Simon Mason
To ensure people are only counted once, Stats NZ uses what it calls a “de-duplication process”.
“We have statistical matching methods that give us confidence in removing duplicate responses leaving us with genuine unique responses. We also have a similar process for dwelling forms to ensure each dwelling is only counted once.”
More reminder letters are on the way, Mason says, even to those who have completed the five-yearly survey.
“We encourage the public to only complete the census once. You may still receive a reminder letter after completing the census, as we may not have received forms at the point that we start printing letters.”
Mason explains it’s by design that every time a census letter is sent, or a pack is delivered, it will contain a different unique access code.
“Each of these codes are private and assigned to a dwelling. We provide a new and unique code every time for people’s privacy and security – if we sent out the same code to a household on every letter, and a letter accidentally went to the wrong house, they would be able to see the household information – the address and names of people living or staying there.”
Households that don’t respond will receive at least two reminder letters. The pre-census day reminders aim to encourage an early response.
“We introduced this pre-census reminder following the 2022 field test for the 2023 Census.”
That’s no surprise. Last year’s field test, in parts of Auckland and Tauranga, happened during the red light Covid setting, and so Stats NZ was forced to remove the face-to-face 'assist' part of the dress rehearsal.
New infringement regime weighed
Stats NZ confirmed it’s not an offence to fill out the census twice. It is an offence, punishable by a fine of up to $500, not to complete it, however. After 2018, Stats NZ took 60 court cases against the worst offenders.
The Data and Statistics Act, which came into force in August last year, enables infringement notices to be issued, on top of the existing ability to seek criminal charges.
The fines for each offence have increased. For failing or refusing to provide data, individuals can now be fined up to $2000. For other offences, such as not complying with a compliance notice, recklessly destroying data, or impersonating a Stats NZ employee, individuals can face a maximum fine of $5000.
Last year, the census board weighed up whether to use infringement notices in this year’s census. However, the idea was rejected (the final decision was made by Stats NZ boss Mark Sowden), as bringing in a new scheme was seen as “high-risk”, requiring “significant additional resource allocation” which “Stats NZ does not currently have”.
Time pressures meant the notices might not be ready in time, anyway.
Discussion from census programme board minutes said “it seemed a punitive approach to use against populations Stats would be encouraging engagement with”.
By 5.30am Tuesday morning, 1.4 million forms had been returned, Mason told RNZ – 96.7 percent online. Statistics Minister Deborah Russell was confident the census would hit its national goal of 90 percent participation.
