To help prevent conversion duplication and support value-based bidding, which unique purchase identifier should be shared?

Transaction IDs are unique identifiers assigned to each purchase. Sharing these with Google Ads prevents conversion duplication by ensuring that each unique purchase is counted only once, even if a user interacts with multiple ads or completes the purchase multiple times. This accuracy is crucial for value-based bidding strategies, as it provides Google's automated bidding systems with precise data on the value of each conversion, leading to more effective optimization. User IP addresses are not unique to a single transaction and can change, making them unreliable for preventing duplication. Ad group IDs identify the ad group, not a specific transaction. Browser type is irrelevant to identifying unique purchases.