Statistics NZ denies massaging building figures

September building consent figures slumped compared with the same month last year but Statistics NZ continued to trumpet a rising seasonal trend.

“The trends for the number of new homes authorised, both including and excluding apartments, continue to rise after dropping to some of the lowest levels seen since these series began. This is despite seasonally adjusted figures for September showing a large decrease ...” Statistics NZ said.

Different versions of the official media release continued to emphasise the “rising” trend, the strength of which remains debatable.

The trend graph shows consent numbers at a similar level to 2009 after a rise during 2010 that has fallen away again.

NBR NZPI challenged Statistics NZ about its emphasis on a positive long-term trend and asked when a monthly rise or fall could affect the trend.

“We have decided to emphasise the trend in the September release as it shows the long-term picture for building consents, whereas if we had just emphasised the decrease in the seasonally adjusted and actual figures, some users may think the figures look worse than the actuality – when really the long-term picture shown by the trend is more of a positive picture,” Karen MacKenzie, statistical analyst at Statistics NZ, said.

“We want to present a balanced story and not just focus on the big changes as there is more to the story than just those large figures. As we also mentioned in the media release, the seasonally adjusted figures have fallen significantly this month but that this is partly due to the strength of the seasonally adjusted figures in July and August. So, although seasonally adjusted figures for this month have fallen, the long-term picture shown by the trend is more positive. We have also tried to add context for the trend, as it is just coming up off the lowest levels that they have ever been at.

“When we add the data for October, the strength and direction of the trend may be revised, depending on the level of the new data point. It is difficult to predict when then trend will change direction, therefore at Statistics New Zealand we are very cautious about predicting future events.

“As you’ve noted, you believe the actual monthly movement was the most newsworthy – and as a reporter we respect your ability to make those decisions. We also take our responsibility to release our statistics in a useful format seriously. This requires us to apply similar judgments about areas of potential interest and in this case, we focused on the trend series,” Ms McKenzie said.

In the September 2011 month, the value of consents issued for all buildings (residential and non residential) was $717 million, down 12% compared with September 2010. Non-residential consent values were down 3.2% and residential consents were down 17%.