2 Aug 2009.
There are three data series that are occasionally cited for layoff data: “Job losers” from the BLS Current Population Survey, “Layoffs and discharges” from the BLS Job Openings and Labor Turnover Survey, and “Mass Layoff Statistics” from the Unemployment Compensation system. Layoffs are inherently more noisy than, say, the unemployment rate or unemployment compensation claims counts, and probably do not add too much to one's understanding of the employment situation.
21 Mar 2008. BLS web site.
http://www.bls.gov/news.release/pdf/mmls.pdf
“MASS LAYOFFS IN FEBRUARY 2008”
“The Mass Layoff Statistics (MLS) program is a federal-state program that uses a standardized automated approach to identifying, describing, and tracking the effects of major job cutbacks, using data from each state’s unemployment insurance database. Each month, states report on employers which have at least 50 initial claims filed against them during a consecutive 5-week period. These employers then are contacted by the state agency to determine whether these separations lasted 31 days or longer, and, if so, other information concerning the layoff is collected. States report on layoffs lasting more than 1 month on a quarterly basis.”