As accounts age, the probability that they will ultimately be collected is decreased. Hence, as a general rule, the larger the number of older accounts that are included in an organization’s AR file, the larger the allowance for doubtful accounts needs to be to reflect the risk. Historical trends in collection success also play an important part in estimating the bad debt losses for the period. A key issue for auditors to resolve, therefore, is whether the allowance calculated by the client is consistent with the composition of their organization’s AR portfolio and with prior years.