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

2nd green button on Main Switchboard:

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

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

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

Bottom green button from Main Switchboard opens:

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

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

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

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

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

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

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

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

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