I've recently noticed a discrepancy between data in Ad Hoc Analysis (Fallout Report) and the corresponding page view metric in Reports (custom event1). Its a substantial difference, varying by a count of close to 10,000. Ive made sure to deselect "count repeat instances" in the Ad Hoc Analysis settings, but it doesnt close the gap any. The data in Reports is the larger number, which makes me think something is happening when the data is being processed.
Anyone know what the culprit may be? Or which set of data I should trust the most? Which should I report on?
Fallout Report will not give you Event Instance (Page Views) rather it will give you Event Visits or Visitors, so you should not compare the numbers.
If you want to match the Fallout Event Visits numbers in report to verify, create a visit segment with Event(Event1 in your case) Exists and select visits as metric. The report number will definitely match the fallout number. Cheers!