View all publications

Annex 6: Quality assurance and quality control

During preparation of the 2005 inventory, work continued on the implementation of the “New Zealand National Greenhouse Gas Inventory Quality Control and Quality Assurance Plan”. Specific checks have been completed as time and resources have allowed.

A6.1 QC procedures implemented in preparation of the 2005 inventory

Tier 1 quality control (QC) checks for key sources (as identified in the level and trend analysis of the 2004 inventory) and a selection of non-key sources were completed on the 2005 data. One of the checklists is included as an example in this Annex (A.6.5). The checks incorporated in the CRF reporter (time-series consistency, recalculation and completeness checks) were undertaken to identify any outliers and inconsistencies in the trends from 1990 to 2005. Additional cross-inventory checks between the CRF tables and the national inventory report for all sectors were incorporated into this inventory submission.

Some specific findings of the 2005 quality control process included:

  • finding and correcting small transcription errors in the agricultural data. These corrections were made during some intensive checking of the sector following the implementation of new data analysis spreadsheets

  • correcting small transcription errors in the waste data spreadsheets

  • adding explanations in the industrial process sector in the common reporting format after a small number were found to be missing.

A6.2 QA procedures implemented

A checklist of recent reviews of specific sectors (including emission factors) undertaken as part of the quality assurance of the New Zealand national inventory is included in this Annex (A.6.6).

In 2006, a quality assurance review of the energy sector was undertaken by an independent consultant. The objective of the review was to ensure the energy sector of the greenhouse gas inventory has assumptions, methods and resulting estimates that are reasonable and an accurate reflection of New Zealand’s energy emissions. Recommendations resulting from this review include developing a top-down energy inventory for verification purposes and having an audit of the energy data file report.

A6.3 Methods of QA/QC used by external agencies

To minimise error, all questionnaires at Statistics New Zealand are carefully designed and tested to make them easy for respondents to understand and complete correctly. During the processing of statistics, checks are carried out to ensure the data appears consistent. Checks are also undertaken to ensure responses have been recorded correctly.

Statistics New Zealand aims to ensure all farms and forests are represented in the agriculture surveys. The survey frame is updated with feedback from survey/census respondents. Statistics New Zealand provides an enquiry service for respondents who need help completing questionnaires and they follow up respondents to ensure high response rates are achieved. Statistical methodology (sample design, estimation techniques) follows international best practice. Data editing and consistency checks are carried out on all data.

A6.4 Future development of the QA/QC system

New Zealand will continue to develop the QA/QC system during 2007. This includes:

  • Redesigning the inventory compilation schedule to allow more time for individual sector and cross-inventory quality checks.

  • Documenting a plan for Tier 2 quality checks.

  • Investigating methods for performing verification of emissions data.

A6.5 Example worksheets for QC procedures in 2005

Example worksheets for QC procedures in 2005 [PDF, 48 KB]

A6.6 QA summary worksheet