TikTok uses data from third-parties to report some metrics.
For example, with the launch of iOS 14.5, we rely on Apple's SKAN API to report app installation and conversion information. In these cases, the metric definition will include "This metric is reported by a third-party" as a disclaimer.
Note: Different third-parties may have various methodologies for calculating these metrics amongst themselves and TikTok. You should consult with the third-party to get more information on the data collection methods, and the latency of reporting to TikTok. Since the methodologies may be unique to each partner, these metrics may differ when compared with TikTok estimates.