The 2018 Census fiasco has spurred Stats NZ chief executive and Government Statistician Liz MacPherson to resign.
It follows the damning independent review of the 2018 New Zealand Census that faced low response rates, delays and limited communication with users.
The report found the running of Census 2018 to be overly complex and ineffective, its leadership lacked strategic direction and effective management, and there was low understanding of how the new census model would perform. Some IT developments were still in development on Census day.
"I accept the findings, we let ourselves and New Zealand down," Ms MacPherson said.
"We were too optimistic, placed too much emphasis on the online census and did not have the robust contingency plans in place for when things started to go wrong."
"When that happened, problems were not escalated to a higher level, we also failed our Treaty partners because we did not convert engagement with Māori into actual Census responses."
Speaking to media today Ms MacPherson said, "I'm sorry, the buck stops with me."
She said response rates, especially for Māori and Pacifika were unacceptably low, and put the census results "at serious risk".
"The census, as carried out on the ground, did not stick to the original plan.
"We put too much focus on the online census. We did not have enough boots on the ground."
State Services Commissioner Peter Hughes supported the resignation, saying Ms MacPherson had "stood up and been accountable in owning the report’s findings".
"She has taken full responsibility for what went wrong, and she is doing an excellent job of fixing it," he said.
Ms MacPherson will stay in the positions until Christmas.
Stats NZ will be releasing the first official results from Census 2018 on September 23.
In the 2018 Census, Stats NZ attempted to adapt technology with principles and methodology adopted from Australia and Canada.
"The changes in approach were necessary to combat the increased costs of conducting a traditional census, and in response to pressure to remain relevant as well as improve the quality and timeliness of census outputs," the report, undertaken by management consultant Murray Jack and international census expert Connie Graziadei read.
The 2018 census had a suite of interdependent IT systems installed, with the new model largely relying on respondents completing the census without the assistance of a census worker.
The report found the way Census 2018 was run to be "overly complex and ultimately ineffective" and its leadership at that level lacked strategic direction and effective management.
Critical IT systems were delayed due to the Kaikoura earthquake and tests were postponed.
"The Data Centre was devastated, rendering IT systems inoperable for an extended period, it took several months for all systems to be stabilised."
Deferring the 2018 Census was discussed, but the 2011 postponement of the census due to the Christchurch Earthquake "weighted heavily in the discussion" - that resulted in the 2018 Census going ahead as planned.
"The IT components were not fully ready for the 2017 Census Test, and some elements were still in development on census day.
"The unknown risks associated with business processes and systems interdependence were carried into production," the report stated.
The decision around what was in the census was made eight months before census day.
"Concerns were raised about this time line but no changes to the planning schedule were proposed. The timing left little time to finalise the questionnaire for both paper and online versions; the most significant impact was the downstream effect on the volume of paper needed to be printed."
The report recommends returning to the traditional census approach of using workers to collect information rather than online, in some parts of the country.