Queensland's crime statistics are "questionable at best and unreliable at worst" due to an "unacceptable" level of inaccurate and incomplete data within the police service, the state's auditor has found.
In a damning review of Queensland Police's reliability and integration of data, the Queensland Audit Office (QAO) said the state's crime statistics should be treated with caution due to a high rate of innaccuracy within the underlying data.
An assessment of the data within the police's QPRIME records system from 2010 to 2016 found 22 percent of all occurence reports with reportable offences were "incomplete, inaccurate, or both".
Around 12 percent of reports to Policelink, the force's public telephone reporting service for non-urgent incidents, from last July to September were incorrect in some form.
Gold Coast officers were specifically singled out for altering crime data statistics by getting victims to withdraw complaints to increase the clearance rate.
The data integrity problems also exist within Queensland Corrective Services (QCS), whose quality assurance processes over its statistics reporting "have long been flawed", according to the auditor.
QCS reported incorrect data on the rate of prisoners and offenders returning to corrective services from 2004 to 2014 because of "outdated data extraction" instructions and poor quality assurance.
"It did not detect its inaccurate reporting of reoffending rates for more than ten years, and its inaccurate reporting of offender to staff ratios for four years," the QAO said.
Police officers have a "poor understanding" of proper data classification rules and practices, and the policy documents intended to guide them are "vague and open to interpretation".
"The Queensland Police Service systems and processes for assuring the quality, completeness, and correct classification of crime data are inadequate," the audit office found.
"The systems and processes do not include monitoring of data and data trends to identify and check for changes that may indicate poor practice or manipulation."
Errors are also made more likely by the lack of integration within the state's criminal justice system, according to the audit office.
There is limited integration between QPRIME, the state's court system, the public prosecutions office, and the Queensland Corrective Services' offender management system, meaning multiple manual points of entry and duplication of effort.
The force attempted to address information sharing within the state through its $62 million integrated justice information strategy program, but the program failed due to poor governance and scope changes.
The crime data quality issues across the state point to "an enduring lack of vigilance ... in reporting reliably and transparently".
"As a result, reported crime statistics are questionable at best and unreliable at worst, and should be treated with caution," the QAO wrote.
Queensland police commissioner Ian Stewart said the issue was fundamentally related to officers not properly understanding the crime reporting classification system.
"And we take responsibility for that," he said in a statement.
"We have some work to do to improve our data processes ... I am not shying away from that.
"We have already implemented many measures to improve the quality assurance processes for our data."