The Los Angeles Times studied more than a million dispatches from the department's database and found that 90 percent of the time, operators took longer than a minute to alert rescue units.
Greuel's report said LAFD data could not be compared to National Fire Protection Association standards due to incidents being "coded unclearly."
The report found fundamental problems of incident reporting, as almost 650,000 of 1.9 million incidents were coded unclearly. As a result, there is no way to determine whether the LAFD has met its 90 percent goal, because emergency incidents were not clearly identified, the report said.
Greuel's report found that overall the LAFD has maintained response time standards compared to earlier periods of budget reduction, but medical first-response times have increased.
The report found medical first-responders' response times have increased by 12 seconds, from 4 minutes 45 seconds to 4 minutes 57 seconds.
Emergency medical responses were even longer in the San Fernando Valley, according to the report, with an increase of more than 20 seconds. East L.A., San Pedro the Metro area responses increased by an average of 18 seconds, according to the report.
The report found that firefighting and non-emergency medical response times have improved, from an average of 5 minutes 18 seconds to 4 minutes 57 seconds.
"Our independent analysis and review of LAFD response times noted that public perception and trust was compromised due to the Department's poor communication of revising their standard of performance measurement and their use of inconsistent methodology in calculating reported results," Greuel wrote in her report.
Greuel's report calculated both the actual response times, which include just turnout and travel, and real response times experienced by the caller, which include call processing. Since July 2009, real response times for EMS have increased by 20 seconds, from 6 minutes and 48 seconds to 7 minutes and 8 seconds. Nearly half of this increase is attributable to a 9 second increase in call processing time, which has increased from 95 seconds to 104 seconds
The report analyzed numbers from between January 2007 and January 2009.