This step is critical as non-pre-processed linkage variables result in a decreased linkage proportion because true matches are more frequently missed . The aim of encryption is to protect participant privacy and data confidentiality. Pre-processing includes three steps: masking (site A&B), creating pre-processing templates (site C) and data cleaning (site A&B). Using masking, the linkage center creates custom pre-processing templates based on the data structure at each site. Advertisement Archived Tweets Load more View all tweets.