With a dud census, the deprivation level of our community is a guess.
If Lakes DHB doesn't get enough money, it affects everybody who needs treatment, Pākehā as well as Māori.
The census is also used to decide how many Māori seats are in Parliament. The calculation is complicated – even with a good census result.
Unless Statistics NZ can track (for example) the ethnicity of every person who comes and goes to Australia, the "2018 Census" Māori population is a guess.
The percentage population of people with Māori ancestry and living in New Zealand has risen over the years. If the increase is big enough, and enough choose the Māori roll, there will be an extra Māori seat in Parliament.
This would affect the boundaries of existing Māori seats such as such as Waiariki.
But Rotorua electorate and its boundaries will also be affected by Statistics NZ guesstimates of where people live.
Electoral rolls can help to fill the gaps in a dud census, but are always unreliable for people who move around a lot. And the police intelligence data base does not cover everyone.
Unless Statistics NZ keeps tabs on everyone individually with all key government departments, the result can only be a "guesstimate".
Statistics NZ needs to publish right now how it will adjust the poor 2018 Census returns. The inquiry into the census asked for this.
And we need a new census, just as soon as possible.
In the meantime we have to rely on the dud census.
- Ian McLean is a former MP for Tarawera, a member of Representation Commission for three electoral boundary changes, and served eight years as a board member for Lakes DHB.