Its testing group overestimated testing capacity because it didn't account for the pooling of samples becoming more or less ineffective.
Pooling means testing a combination of several samples, which can be processed much quicker if the lion's share are negative. Each individual sample is only tested if the pooled sample is positive.
Overall capacity with pooling is roughly twice as large as single-testing capacity. But once Omicron started spreading as widely as we all knew it would, pooling became more redundant as more samples needed to be individually tested anyway.
It's worth outlining these details because it illustrates how basic an error this was, and how easily it should have been anticipated.
But no one in the ministry group seemed to pick up on this, even though labs across New Zealand had warned about it, and even though the ministry was supposedly monitoring the Omicron outbreaks in Queensland, New South Wales and Victoria, where pooling also quickly became redundant.
The ministry also overestimated usable capacity by adding together individual lab capacity from all over the country, even though other labs couldn't share the load because their systems weren't compatible.
Again, seemingly basic stuff.
The impact was not just the delay in processing tens of thousands of tests, which slowed down all the flow-on actions to encircle contacts and contain the outbreak as much as possible.
It also meant there was no projected date for when PCR testing capacity would be exceeded, which should have triggered a shift to using mainly rapid antigen tests. Having such a date would have provided a clear timeline for procuring enough RATs.
Instead, the RAT rollout wasn't ready, the backlog got bigger, and the outbreak was less contained than it otherwise would have been.
None of this means that the ministry won't learn from it, and no one expects a perfect response in the face of a constantly changing pandemic where the only certainty has been uncertainty.
But the errors seem so basic that it does nothing to bolster confidence in the pandemic response as we face winter, and as the subvariants BA.4, BA.5 and BA.2.12.1 are detected in the community.
These are considered more infectious than the previous Omicron subvariants, and pose a greater risk of reinfection if you've already had the virus.
There is little so far to suggest they pose a greater risk of severe disease or hospitalisation, but greater infectiousness alone - especially in combination with winter - will put more pressure on hospitals; the spread of BA.4 and BA.5 are already thought to be behind an increase in hospitalisations in England.
Meanwhile, the ministry is still unclear on its formal advice for people who have finished their seven-day isolation period following a positive RAT result.
Previous advice on the Government's Covid-19 website said that taking a RAT after you've finished the isolation period "will likely show as positive but that does not mean you are infectious".
This had public health experts rightfully indignant. It was effectively government advice telling likely infectious people that they could return to work or school.
The advice has since been updated to say that you shouldn't end your isolation until you've been symptom-free for 24 hours. But what if you're still testing positive?
On Tuesday, the ministry's chief science adviser Dr Ian Town still couldn't say what you should do in this scenario, and that advice was still being considered.
Director-general of health Dr Ashley Bloomfield said that a positive result may not mean you can infect others.
"So here's my advice: Even after your seven days, be careful. You are not required to isolate, in which case, if you're not symptomatic, it's certainly within your employer's rights to ask you to go back to work," Bloomfield said.
"But keep wearing a mask. Avoid places like age residential care or visiting elderly or relatives or friends who might be immunocompromised for a few days ... some people will continue to shed the virus after seven days."
Surely if you're still testing positive, you should keep isolating.
This aligns with the preparedness motto of hoping for the best but planning for the worst, which is a lens that's often used by the continuous improvement group led by Sir Brian Roche.
He has previously been dismayed at how his team's reviews tend to repeat the same recommendations, such as being more prepared and less reactive.
Let's hope that the ministry does all it can to ensure the next review of the pandemic response concludes something other than history repeating.
