Quality Assurance & Quality Control (QA/QC)
Throughout the inventory compilation process the following QA/QC tasks take place to ensure that the inventory quality is maintained and improved, that the inventory is transparent and consistent internally and with other government statistics and is compliant with international guidelines on QA/QC and good practice.
Figure below provides an illustration of some of the key QA/QC concepts that are important in inventories, and helps illustrate our approach to controlling and improving quality.
The UN/ECE and IPCC have provided detailed information about what is 'good practice' for QA/QC procedures in emission inventories. The QA/QC procedures are applied to the whole inventory at all times.
The current systems used by Ricardo-AEA in preparing the UK emissions inventory include:
- at the end of each reporting cycle, all the database files, spreadsheets, online manual, electronic source data, paper source data, output files are in effect frozen and archived. An annual report outlining the methodology of the inventory and data sources is produced. Electronic information is stored on hard disks that are regularly and automatically backed up. The NAEI and contacts databases are automatically backed up every hour from 07-00 to 20-00. Paper information is archived in a roller racking system and a database of all items in the archive is used
- there is an online system of manuals, which defines timetables, procedures for updating the database, document control, checking procedures and procedures for updating the methodology manual
- data received by Ricardo-AEA are logged, numbered and should be traceable back to their source from anywhere in the system
- the inventory is held as an Access database of activity data and emission factors. Within the database these data fields are referenced to the data source, or the spreadsheet used to calculate the data. For fuel consumption data, the Table numbers in the Digest of UK Energy Statistics are identified
- the database specifically identifies the units of both activity and emission factor data
- when revisions are made to the methodologies of the estimates, emissions for all previous years are recalculated as a matter of course
- estimates are made of the uncertainties in the estimates
- the final checks on the inventory involve a 'why has this source changed since last year' exercise performed by a designated auditor. Inventory staff are required to explain significant changes in the inventory to satisfy the auditor
Page last modified: 25 February 2013