Unexpected Master Records in Preview

The Master Record Preview in Merge & Survivorship shows which record within each matched group will be designated as the master — the record that "wins" and whose values are carried forward. If the preview is showing an unexpected record as master, the rules need to be adjusted.

How Master Determination Works

Each master rule evaluates a field across all records in a group and assigns a win to the record with the best value (e.g., Longest, Max, Most Popular). The record with the most wins across all active rules becomes the master. In the case of a tie, rule order is used as a tiebreaker.

1. Check Rule Ordering

Rule order matters when there is a tie in wins. If two records each win an equal number of rules, the higher-priority rule (lower order number) determines the master.

Fix: Drag rules to reorder them. Put your most important or most reliable rules at the top. If a specific field is a strong quality indicator (e.g., the record with a populated email address should always win), move that rule to a high priority position.

2. Null Fields Skewing Results

Some operations, such as "Longest," can be won by a record with a non-null value even if that value is short, simply because the competing records have null values. A record with mostly empty fields can accumulate wins if the other records also have empty fields in those columns.

Fix: Consider using First Non-Null as an operation for fields where presence of any value is more important than the specific value. Also review which fields are included in rules — remove rules for fields that are consistently null across all records.

3. Manual Master Designation Override

In the Match Results module, individual records can be manually designated as the master using the crown checkbox. Manual designations take precedence over all automated master rules.

Fix: Go to Match Results, find the affected group, and check whether a manual master has been designated (look for a filled crown icon). Clear the manual selection if you want the rules to govern master selection instead.

4. Data Source Filtering Exclusions

Some master rules allow you to restrict which datasources are eligible to win a particular field (the "Take data from" or "Prefer data source" setting). If a rule excludes the datasource of the record you expect to win, that record cannot win that field.

Fix: Review the datasource filter settings on each rule. Ensure the datasource you expect to produce the master record is included in the eligible sources for the key rules.

5. "Most Recent" Date Interpretation

If you are using Most Recent as a master rule, MatchLogic interprets the date field according to standard date formats. Dates stored as text strings may not sort correctly.

Fix: Verify that date fields used in Most Recent rules are formatted consistently and recognized as dates by Data Profiling. If they are stored as text, apply cleansing to standardize the format first.