P&S Data Quality

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Discussion from March 28, 2006

== Objective Create a common set of data quality metrics across all Federation data products. Data providers can provide measures for their own products. 3rd parties can provide their own ratings. Quality can refer to accuracy, completeness, and consistency. It is not clear how to measure consistency. It is desirable to provide quality assurance.

We would like to create a 1-10 Data quality scale, where:

 1 = no accuracy claimed
10 = fully reliable data that has withstood the test of time

This measure can be applied to any of the quality dimensions:

Quality Dimensions

1. Sensor/Instrument (well calibrated, stable, checked across instruments, V/V)
2. Spacecraft (locational and communication accuracy)
3. Environment Issues (contamination from clouds, rainfall, ground, sea, dirt, etc.)
4. Data Processing (accuracy of interpolation, algorithms, ancillary source data)

Our Task

Specify classifications on the 1-10 scale for each dimension

Other topics

Quality assurance (someone tags it as valid)

Useful metadata provided?

Instrument Verification and Validation

Data processing

Re-processing tag and notification

input errors and forcings

re-gridding

missing data

Usage issues

High enough resolution?

Valid inference about what is measured

Chain of Custody (for legal use)

Completeness Can we come up with categories of data completeness?

3rd party ratings

NCDC

NCDC Certified data (only states that it is in the archive)

GCMD

DIF records have some minimum required fields to accept

then have a text field to describe quality

ECHO

"measured parameters" from ECS model

QA percent cloud cover; missing pixels;

CLASS/Climate Data Record

Maturity Model approach for data (John Bates application from software maturity)

Level of maturity (five levels of improved treatment)

See CDR Maturity paper

FGDC

Whole section on quality, text only

Testimonials

Peer review

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Discussion

Completeness

• Is this a measure of quality?

Depends on stated offering from the provider; if they claim it is complete and it isn't

Assertions about datasets

We may want some standard for claiming and measuring how valid a claim may be

Additional Questions

• What common data quality standards can the Federation offer within the Earth Information Exchange?
• How can we enforce these standards within the Earth Information Exchange?
• Are there similar ratings for "data services"?

Action

Rob will send advertisement to the whole group for next months meeting.