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Adaptive data correction at remeasurement: What to do when errors are discovered?

2011 National FIA User Group MeetingSacramento, CA

March 8-10, 2011

Bill BurkmanSouthern Research Station

FIA Program Manager

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Objectives of Presentation

• Define the issue• Possible solutions• Implications of the solutions• Discussion and questions

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Quality Assurance Program• Field data collection:

– Crew Training– National Field Guide– Quality control data collection– Corrective action

• Data processing checks:– Range or valid code checks – Logic checks– Analyst review of draft output

• For more detailed information – Phyllis Adams, National FIA QA coordinator

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Current data correction procedures : Field data collection

activities• Field data recorder procedures:– Crews are given some information: dbh, azimuth,

species, etc.– Some variables are “hidden” ; “hidden variables

are only shown to crew if there is a logic check discrepancy

• Data checks:– Range or valid code checks – Logic checks: compare two variables from T2 or

compare same variable from T1 and T2

• Crews have option of providing note

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Current data correction procedures : Data processing

activities• Same checks are evaluated during data processing• Additional edits are evaluated during data

processing • Analyst review of draft data – QA tools in

development• Some checks are geo-spatial• Estimates of change are impacted by current

processing; generally based on T1 values• Some major issues are sent back to the field for

verification

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Current data correction procedures : Issues

• Unusual results can result from basing on T1 values:– Reserve status – e.g. removals from reserved land– Stand origin – e.g. pine plantation changing to

natural hardwood stand– Land use changes - – Species

• When to change and how far back to go?• What happens if “fixed” data does not match

previously published information?

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Solutions???• Assume T2 is correct and fix T1 – possible

but may not be practical in all cases• Provide additional tools and checks in

data recorder program so T2 crew can update

• Complete QA tool development and deploy

• Other solutions?

Discussion and Questions

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