Compare sources by scope, timing and method before treating them as contradictory. Two records can answer different questions. Synthesis should preserve what each supports and identify what neither establishes.
Worked example
One record counts entries and another counts unique visitors. Different totals may result because the units differ, not because one record is false.
Original fiction: Stocks and Loans
Two fictional library records report different quantities. An inventory lists 240 books on the shelves at closing time. A loan log lists 37 checkout transactions during the day, including a book checked out twice after being returned. The inventory does not list books currently on loan, and the log is not a count of distinct titles. Neither record alone gives the library's total collection size.