CODES 2000 User Forum -- Tech Note #16
Imputing Complete, One-to-One Dual Linkages
Applies to: CODES 2000 Release 2.2.373.
Last updated: Friday March 29, 2002.
SUMMARY
CODES 2000 Release 2.2.373 builds linkage imputation and one-to-one match selection into the process of merging match passes. After all match passes are merged into the Match Pairs In Sets table, a new Linkage Imputation Wizard imputes one or more complete many-to-many matches. Next, the Wizard derives a one-to-one match from each many-to-many imputation. The new Wizard assigns record pairs to sets independently after each imputation. The earlier stand-alone Linkage Imputation Wizard assigned pairs to sets once in the complete Match Pairs In Sets table before doing any of the imputations. The old approach resulted in sets having thousands of members in some states.
PROCEDURES
- Merge all match passes.
Perform all match passes of interest with the CODES 2000 Perform Match Wizard.
Click on the Merge command button.
Confirm that you want to merge all complete match passes.
Note successful creation of the Match Pairs In Sets table.
Here is the Match Pairs In Sets table referred to in the progress message. Note that the table now includes a Match Probability field.
- Provide information for the Linkage Imputation Wizard.
The Linkage Imputation Wizard allows you to create from 1 to 20 separate linkage imputations from the Match Pairs In Sets table.
Enter the number of linkage imputations you want to create and click OK to start the imputation process.
Or, you can just select all matched pairs above a cutoff probability. Selected matches are treated as imputation 0. Note that specifying a cutoff probability less than that in your link specifications will not create any new links. Specifying probability 0 will guarantee that all pairs in the Match Pairs In Sets table are selected.
- Note progress in the imputation process.
First each imputed complete many-to-many linkage is tabulated in a separate table named ImputedPairsInSets1, ImputedPairsInSets2, etc. The Wizard assigns record pairs to sets independently in each imputed table.
Here is a typical Imputed Pairs In Sets table.
Next, a one-to-one match is derived from each many-to-many imputation. The one-to-one match tables are named LinkedPairs1, LinkedPairs2, etc.
The Wizard notifies you when each imputation is complete with the following progress message. If you specify a cutoff probability for the Wizard, the results are tabulated in LinkedPairs0.
Here is the LinkedPairs1 table referred to in the progress message. The table can be found in the appropriate link database, CrashEMS in this case.
