PERM cases are actually applications for labor certification. The PERM Rule has only been used since 2005, when the it became effective, to describe applications for labor certification filed or after March 28, 2005. Applications filed before that date (some of which may still be pending) are not subject to the PERM Rule.
The Department of Labor processes pre-PERM cases according to the old rule and PERM cases according to the new rule.
Prior to PERM, applications were filed in local offices of the State Workforce Agency. Processing times varied considerably, but a "fast" processing time in the SWA would have been about one year, and a "slow" processing time in the SWA would have been 3 years or more.
After leaving the SWA office, applications were forwarded to the Federal Regional office, where they entered into a new line of processing. The Federal Delays also varied up to several years.
As a result, in some cases, applications could take more than five years to be processed.
If remands for additional evidence or appeals were required, this would add additional processing time. Some unusual cases might have taken as long as 10 years to be completed at the Department of Labor level.
PERM was introduced, in part, to reduce backlogs. In the beginning, PERM cases met the expectation of no more than 60 days for initial processing.
However, as may be expected, delays ensued, and processing time for PERM cases increased.
Although initial PERM processing may be expected in a matter of months, or up to a year, audits and remands may increase processing time. Recently, remands (responses to audits) were taking about two and a half years to be processed!
In other words, the entire processing was beginning to approximate the pre-PERM processing experience.
The DOL maintains information about processing time on its site: http://icert.doleta.gov/
According to DOL, they are currently processing cases filed in December 2009, but where audits are concerned, there is a delay from July, 2008.
As with most agencies, the processing times are subject to interpretation and explanation. They may be calculated not from the date of postal receipt at the agency but from other date, and certain lapses of time within the different phases of the process may not be taken into consideration. In additional, in actual process, some cases may be processed sooner or later, so that strict adherence to the published figures should not be expected.
Getting back to the original inquiry, how long does a PERM case take, my guess would be about 1-4 years, and don't forget, a PERM case is not processed until AFTER the recruitment period, which may take up to 180 days!