IPT

Accreditation, Communication and Interlaboratory Proficiency Testing Data Site

This program aids laboratories to verify the proficiency of the testing capabilities both for Nadcap Materials Testing compliance in accordance with Nadcap AC7101 and international specification requirements of ISO/IEC 17025. The purpose of the interlaboratory testing comparisons of this program is to evaluate the overall laboratory testing performance. For current IPT Program test summary results, please select:

3rd Quarter 2003 Test Results

This program consists of homogenous, qualified material sent to all participating laboratories. Each testing method has an enrollment period and a reporting period. All testing data is coded and electronically record, which means that a real-time review of the overall mean results is possible. For a process flow document, please click here

The PRI/Nadcap IPT Program will vary from year to year. Both a current schedule of tests, plus an extended schedule, have been established.  Please click here for more details.

Why take part in the IPT Program?

The Proficiency Test Program provides a consistent output format and series of analyses to maximize the benefits of the program and support our clients’ needs. For information on IPT versus “Round Robin Tests”, please click here

• Ability to identify any individual inconsistencies for improvement
• Ability to identify any consistent biases for improvement
• Ability to maintain accredited status based on ongoing performance

• Establish whether a supplier demonstrates proficiency that merits continued accreditation
• Observe if a supplier maintains in-control testing processes over time
• Substantiate effectiveness of Nadcap accreditation for special process control of materials testing laboratories
• Establish if available testing provides data of sufficient quality

• Determine actual industry performance
• Identify areas where the industry needs to improve data accuracy / reliability
• Identification of best practices

This site provides resources and analytical & communication tools to support PRI/Nadcap’s Materials Testing Laboratories Accreditation and Interlaboratory Proficiency Testing Programs for Metallic Materials Testing Laboratories. We encourage contribution and review of best practices included on this site – please click here for more details.

This site includes a set of technical programs and guidelines needed by laboratories and their global customers to ensure that the testing certifications for materials and hardware evaluations are accurate. These guidelines focus on the latest technologies available to the materials testing industry. Please click here for more details.

In addition, this site provides the following features:

1. Data presentation and analysis of each participants results for each property

• All participants' data assembled in a table for each property or of all properties as practical
• Initial population statistics calculated
• Initial individual statistics calculated
• Outlier data identified and excluded
• Final population statistics recalculated
• Outlier data restored
• Final individual statistics recalculated
• All participants' performance displayed in an intuitive and useful visualization for each property

2. Summary analysis of all participants performance as a group

• Assemble final population statistics in a table of all properties
• Group's performance displayed in an intuitive and useful visualization for each property showing:
• Number of Participants (n)
• Range (smallest data, largest data)
  - Mean (X-bar)
  - Standard Deviation (s)
  - A frequency distribution plot, showing the mean, 1s and 2s

3. Identification of problem participants and generation of NCRs

• Objective determination based on previously agreed and published criteria
• Pass/fail criteria reflect practical needs of user community as well as a fair expectation of capability of current technology applied by a fully proficient laboratory.
• Review by task group to adjust criteria if predetermined criteria fail to yield rational outcome
• No individual user review
• Replacement tests after data due date or results publication, are not valid NCR clearance
• Scope of corrective action required to clear NCR will depend on number of properties for which performance fails to meet criteria and severity of failure

Proficiency criteria are not based simply on a certain number of standard deviations, i.e. a particular maximum h statistic, because, if all the labs are in excellent agreement, the standard deviation becomes very small. This would cause labs to receive NCRs for very small errors, far smaller than supported by the technique or the standards available.

To be judged Highly Proficient a laboratory's values must fall within the greater of the following:

• within +/- 1 std dev (h less than/equal to +/- 1.0), or
• 1 least significant digit of the value based on the defined limited number of decimal places they must report.

To be judged Proficient a laboratory’s values must fall within the greater of the following:

• within +/- 2 std dev (h less than/equal to +/- 2.0), or
• 2 least significant digits of the value based on the defined limited number of decimal places they must report, or
• the intrinsic limiting factor to the test, if one exists (i.e. the typical variation on a hardness standard block)

A laboratory having a value falling outside these criteria would be judged Not Proficient and an NCR generated on a property-by-property basis.

In each proficiency test, the criteria will be tested to see that they give a rational outcome before being relied upon. The level of difficulty will be appropriate to the user's needs and provide a high standard, but still be survivable by a competent, properly equipped laboratory.