What in the World is PWL?

An assessment of the product quality is needed no matter what characteristic is being measured. Percent Within Limits (PWL) is a quality measure that combines the sample average and standard deviation into an estimate of the population. PWL is a measure that has been used by the Department of Defense since 1958 and is now used by over half of the State Highway Departments (SHD), the Federal Highway Administration (FHWA), and the Federal Aviation Administration (FAA). Three advantages to the use of PWL or its complement Percent Defective (PD) are 1) it can provide an incentive for contractors to improve their variability and provide a more uniform product, 2) there is software available that can easily calculate and balance Agency Risks and Contractor Risks, and 3) it is compatible with American Association of State Highway and Transportation Official (AASHTO) standard recommended acceptance plans.

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  • English

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Filing Info

  • Accession Number: 01041407
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jan 30 2007 1:29PM