1. Final Data Review and Invalidation
3rd Phase of Data Review, when data can be excluded from AQS files, reports/charts, and calculations

2. 2nd green button on Main Switchboard:

3. 3rd Phase of Data Review-Final
Review all data you have flagged
Then make a decision on whether to exclude the data from AQS files, reports/charts, and calculations
To exclude data, choose an invalidation code
The invalidation codes are the AQS null value codes
You should perform this step quarterly, or more frequently, so bad data are excluded from your reports and charts

4. Terms we use (consistent with AQS):
Qualifying = flagging
Helps you find this row (record) later
Shows reason for flag
Meant to alert you that there might be a problem with this record
May have multiple flags (usually several reasons for suspect data)
We already flagged data in 1st and 2nd phases

5. Invalidating data: NEVER delete data!
Invalidating = deciding not to use
in internal reports, charts, and calculations
AQS files
Invalidation codes show reason for not using that data
Toolbox stores AQS null value codes in separate column, so all data and flags are kept

6. Bottom green button from Main Switchboard opens:

7. Final review of PM10 Continuous Data:
This screen looks like the qualifying screen, what is different?

8. In this 3rd phase, you only review already-flagged data:
Clicking on the “View All Qualified Data…” button only shows data that you have previously qualified (flagged), therefore…
…only qualified (flagged) data can be evaluated for invalidation
Another reason to flag any questionable data in the 1st and 2nd phases

9. Continuous PM10 Example
In this example, how many records will show up when I click on the “View All Qualified Data…” button?
Click here to find out

10. Only 8 records in this example
Only the 8 qualified (flagged) records in the two week period are available for invalidating, not all of the records in the two week period

11. How Do I Invalidate Data?
Determine whether or not to invalidate each qualified record based on your best judgment
For each record that you decide to invalidate, click in the Invalidation Code field
You will get a drop-down arrow button
Click on that drop-down arrow button to bring up a list of codes
Choose the code that is most appropriate
You can choose a different code for each record

12. Choosing an Invalidation Code
Flags you assigned during 1st and 2nd phases of data review
3rd phase: Null Value Codes

13. Data may have multiple flags:
You evaluate existing flags and assign an invalidation code, if you think data are “bad”

14. Invalidation codes:
Can be changed or removed if you get new information
Often judgment call on which code to use
Codes “prove” to EPA that you were trying to collect data, and have a reason for no data for that hour

15. Remember
You qualify data during 1st and 2nd phases of data review process
You must qualify the data record during 1st or 2nd phase of data review before it can be evaluated for invalidation
You invalidate data only during 3rd phase of data review
Only way to exclude the data from AQS files, reports/charts, and future calculations