Environment Aotearoa 2015 and Environmental indicators Te taiao Aotearoa present data that fall in one of three categories: either a national indicator, a case study, or supporting information. These categories reflect the quality of the available data, measured against the Principles and protocols for producers of Tier 1 statistics (Statistics NZ, 2007). We assessed the data against six criteria: relevance, accuracy, timeliness, accessibility, coherence, and interpretability. Relevance and accuracy are the core criteria.
Data used in:
- national indicators: rates strongly on relevance and accuracy, and meets at least three of the four other criteria
- case studies: rates moderately on relevance and accuracy, and meets at least two of the four other criteria. A case study is used when it can further illustrate a national indicator, or explain an area of interest that is not measured nationally
- supporting information: rates moderately on relevance and accuracy, and provides useful information about a particular aspect of the environment or a domain.
We report on the environment only where reliable and accurate data are available. Because of this, there are gaps in our information. Because of the time it takes to collect, assess, and prepare data for publication, most data are to 2013 – except in a few cases where we could include 2014 data.
For an explanation of these gaps and areas for improvement see: Data needs and improvements chapter.
To understand how aspects of the environment have changed over time, we have done ‘trend assessments’ on most data with sufficient time series and accuracy. These assessments show ‘statistically significant’ decreases or increases at the 95 percent confidence level. When we refer to a decrease or increase being ‘statistically significant’ in Environment Aotearoa 2015, this means that we assessed it as showing a statistically significant trend.