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## GRID Quarterly Facility Calculations

Modified on: Wed, 1 Sep, 2021 at 4:14 PM

### Data in the *GRID Quarterly Facility Report* is derived from the numbers submitted monthly. We then take the average of the numbers the facility provides for each measure. When we find anomalies, we advise facilities of them before the end of the reporting period, so they have a chance to correct the data.

### For example, assume you reported the following radiography turnaround times (TAT) in your monthly data:

### July - 45 hours

### August - 48 hours

### September - 24 hours

### October - 24 hours

### November - 24 hours

### December - 24 hours

### Based on the other numbers provided, we can see July and August had data anomalies. For example, for July:

### Number of exams completed – 697

### Number with TAT < 12 hours – 200

### Number with TAT between 12 and 24 hours – 200

### Number with TAT between 24 and 48 hours – 297

### Given these numbers, the mean TAT reported of 45 hours for July is mathematically impossible. Even if we assume the maximum value for each input, e.g. all exams signed within 12 hours were signed in exactly 12 hours, the mean TAT must be less than 31 hours. Because the correct number could not be determined, it is not accurate for calculating this measure for the 6-month period. The same thing happened in August. So that leaves us with September through December, for which you reported 24 hours for each month. The average of those four months is 24.

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