Perform Triple. When you click on Perform Triple the following steps are performed for each imputation. 1. Candidate triples (Triple__MT1, etc.) and associated posterior probabilities are selected automatically from tabulated merged pairs by finding all pairs in two different dual matches with a common record. 2. Comparison outcomes from the dual matches are tabulated for each match field. 3. Posterior probabilities are calculated for each candidate triple. For dual matches, candidates can only be true matches or unmatched. For triple matches, candidates can be true triples, true A -- B only, true B -- C only, true A -- C only, or unmatched. A posterior probability is calculated for each possibility. Goodness of fit for a triple match with simulated data is measured is the same way as for dual matches. 4. Disposition of each candidate triple is imputed by a random draw from the calculated posterior distribution. 5. Associated dual match pairs are extracted from each imputed triple match. Extracted pairs are listed in tables like the imputed pairs and linked pairs tables for dual matches (Triple__CrashEMS__IP1, Triple__CrashEMS__LP1, etc.). Pairs that are not part of imputed triples are imputed using the same dual match probabilities as used in the past. If the candidate triple in the earlier example became an imputed triple match then the pair (Crash record 1, Hospital record 3) would be included even though it was not in the merged pairs for the Crash, Hospital dual match. So, there is a potential to pick up missing dual matches by doing a triple match.
Review Triple. When you click on Review Triple a table of merged candidate triples is displayed (Triple__MT1, etc.). Candidate triples are numbered sequentially. Each is identified by a different combination of Unique IDs from Sources A, B, and C. Posterior probabilities from the three dual matches are listed as Prob AB, Prob BC, and Prob AC. If a candidate was missing from a dual match (not tabulated as a merged pair) then 0.01 is listed as the posterior probability. You might be able to improve your dual match specifications if you investigate why such pairs were missing from dual match results in the first place. Calculated prior and posterior probabilities are listed for each possible imputed disposition (T = Triple, AB = A -- B only, BC = B -- C only, AC = A -- C only , U = Unmatched). Imputed disposition for each candidate triple is listed using the same coding scheme. Comparison outcomes are listed for all match fields. Outcomes are coded using A for Agree, D for Disagree, and M for Missing. For example, outcome ADD means that a match field Agreed in Match A -- B, Disagreed in Match B -- C, and Disagreed in Match A -- C. Outcome MMA means that a match field was Missing in Match A -- B, Missing in Match B -- C, and Agreed in Match A -- C.