More than $16 billion in overdue taxes were written off as uncollectible by Internal Revenue Service field offices last year, five times the amount that was recovered, according to the Treasury Inspector General for Tax Administration.

TIGTA blamed poor standards for determining which delinquent taxpayers to target. Little attempt is made to discern who is most likely to be able to pay, or to select more current cases where collection is most likely, TIGTA said in a report made public Oct. 9.

As a result, $16.1 billion in delinquent taxes were written off as uncollectible by field officers in the 2013 fiscal year, while only $3.1 billion was recovered, according to TIGTA.

There is a three-tiered system of collecting money owed to the federal government, including written notices, phone contacts and in-person collection from field offices.

The TIGTA report focuses on field collections. In selecting cases to pursue, field officers do not always consider how old the case is, the financial condition of the taxpayer or whether prior attempts to collect tax debt have been unsuccessful. The IRS also does not measure agent productivity or establish specific criteria for selecting cases.

As a result, many of the cases assigned for collection have little chance of success, while others that have better prospects go unassigned, according to TIGTA.

“The field workload selection process is not designed to ensure that cases with the highest collection potential are identified, selected, and assigned to be worked,” TIGTA found.

“The IRS has a large inventory of taxpayer delinquent accounts but limited resources to collect the unpaid taxes,” according to the report. “If sufficient steps are not taken to make the most effective use of collection resources, it can have a substantial impact on the amount of Federal taxes that remain uncollected.”

IRS officials generally agreed with TIGTA’s findings and said they are implementing new rules to fix the problem.

TIGTA reported in August that IRS employees may not be properly closing more than half of all uncollected delinquent tax cases. There was no evidence that IRS employees completed all of the required research steps for 57 percent of the cases prior to their closing, TIGTA found.