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PWL & Pay Factor Tables

From: Rick Bradbury
Date: 20 Nov 1998
Time: 14:52:24
Remote Name: 141.114.130.70

Comments

Many highway agencies that have moved or are moving to statistical QC/QA specifications are using percent within limits tables and corresponding Pay Factor tables that I believe are based on Mil Spec 414. Operating Characteristic curves show that the Pay Factor table overpays producers. Most agencies define the acceptable quality level as 95 percent within limits, at which 100 percent pay is awarded. Under these tables, 95 percent within limits pays on average 103 - 104 %. I believe that instead of minimizing the risk of rejecting the product at the AQL to 5%, the table minimizes the risk of awarding payment less than 100 % to 5%. I believe this unfairly tips the balance of risk in favor of the producer. Does anyone have any background material on Mil Spec 414? The PWL and Pay Factor tables are used by many state DOT's. The PWL tables are also used by the FAA on airport construction projects. Any help would be appreciated. Thank you.


Last changed: November 20, 2007