The National Electrical Manufacturers Association (NEMA) published NEMA LSD 63, "Measurement Methods and Performance Variation for Verification Testing of General Purpose Lamps and Systems." NEMA LSD 63 establishes variations that can be expected when independent verification testing, generally based on small samples of lamps or ballasts, is performed to estimate product performance characteristics and for comparison to manufacturer’s ratings.
NEMA LSD 63-2012 is available at no charge.