As with all metric research on WikiRate, it really helps if researchers make a comment describing exactly where within the source you found the information.
When adding, editing and checking data please consider including the following details:
Page number - where the metric value was found in the report
Conversions - include details of any simple or complex conversions made to determine the metric value
Calculations - include details of any simple or complex calculations made to determine the metric value
Company methodology - include details of the companies methodology used to determine the value reported (if reported)
Include any additional information relating to the metric value in the comments so other users can easily understand the answer.
For GRI metrics in particular, the sources can be very large documents, and if another researcher would like to check the metric value this information makes life much easier!