A number of key questions are posed by this surprise outcome. This include why the Justice Department repeatedly gets these predictions so wrong and was there a reduced inflow of prisoners over the period in question, or did more than normal get released.
After those key questions are satisfactorily settled there should be a review of what, if any, new strategies did Corrections or the other players in the Justice sector adopt over the period and what effect these might have had on the prison muster.
With the mega-jail off the table, we can assume that many in the aforementioned Justice sector began to take seriously the Labour-led Government's objective of reducing the prison population by 30 per cent over time and to look for "low hanging fruit" which they found.
One simple idea that I mentioned in a previous column without realising that it was already getting tested is called "parole-ready".
This programme supplies specialist advisors to work with long-serving prisoners to ensure that they have improved access to rehabilitation programmes and good plans for release.
Perhaps the most important task these advisors provide is guidance for illiterate prisoners in filling in all the forms required before an appearance in front of a Parole Board can occur.
Another initiative managed to speed up the remand process and make a serious dent in the backlog of prisoners on remand, many of who go free as soon as they manage.
This Corrections-led initiative was a rare but encouraging example of collaboration between the Police, the Courts and Corrections. May we have many more of these.
A pilot scheme which is showing real promise aims to extend electronic monitoring to many more defendants by assisting those with literacy problems to fill in the forms to make the necessary applications for this kind of monitoring in preference to going to jail.
Further innovative thinking by the Corrections Department includes greater assistance in finding accommodation for offenders who qualify for home detention and Smartphone applications which help defendants comply with their bail conditions and therefore avoid a spell in jail.
My guess is that some long term strategies are also finally beginning to pay off and should be stepped up.
One of Judith Collins' contributions as Minister of Corrections was the establishment of two Drug and Alcohol Courts in Auckland and Henderson.
These Courts substitute monitored abstention from drugs and alcohol for a jail sentence and there can now be no doubt of their success in getting a small proportion of those offenders lucky enough to be assigned to those Courts living normal lives and avoiding jail.
It is high time these trials were declared the successes they clearly are and the model extended to places like Hawke's Bay where the need is obvious and immediate.
Another slow-burning scheme which is starting to get traction is the promotion of post-release employment.
Senior Corrections manager, Steve Cunningham, has been beavering away at lining up employment for prisoners on release for some years now and has slowly but surely sold the idea to an increasing pool of employers.
Shortages of Labour obviously help Steve in his quest, but he deserves real credit for the success of a strategy which research tells us is the best way of reducing reoffending.
To get the kind of long term reductions in prisoner numbers that were achieved in some States of the United States there will need to be a greater focus of normalising prison life, promoting in-jail education and building prisoner's skills, but let's give Corrections some kudos for a good start.
■ Mike Williams grew up in Hawke's Bay. He is CEO of the NZ Howard League and a former Labour Party president.