Answer:
The use of the allowance method of accounting for bad debts.
Step-by-step explanation:
The matching principle is one of the cornerstones of accrual accounting, since t states that when revenue is recorded, you must recognize all related expenses with it. E.g. you cannot only record sales revenue, you must also record COGS. Regarding bad debt expense, the matching principle states that the provision for bad debts (allowance for doubtful accounts), must be recorded in the same accounting period.
So the revenues generated by credit sales have to be matched to both COGS and a provision for uncollectible accounts or bad debt. US GAAP establishes that estimates for bad debt should be recorded in the allowance for doubtful accounts, although the estimation method is not mandatory.