What Methods are used to calculate missing data from accounting records?

Incomplete records can be verified through tracing to General ledger,Ledger and sub ledger account.Control accounts can be used to compile the balances of different elements of financial statements e.g Cash book and Purchase ledger to compile Purchase ledger control account.Closing balances of balance sheet and income statement can be calculated through GL ,Sub Ledgers accounts.Inventory,Cash,Receivables,Payables etc

Whereas in Auditing Substantive Analytical procedures,TOD & TOC can be used to verify and calculate the incomplete record.Tracing ,Vouching .GL Testing ,Sampling etc

The simplest is Net Assets basis.