Interlaboratory Study Program
ASTM's Board of Directors adopted plans, in the fall of 2004, to launch the Interlaboratory Study Program (ILS)
as part of their continuing pursuit of excellence in standards development. Responding to the need for standards
in the marketplace to be of known and documented quality, a commitment was made to fund the development of the
ILS Program. This commitment means that ASTM has been able to assist those technical committees for which the
prospect of implementing an interlaboratory study was either administratively daunting or financially
impossible. The ultimate goal is to enhance the quality of ASTM standard test methods by aiding the Technical
Committees as they develop Precision Statements backed by high quality laboratory data.
In order to support the committees in their efforts to produce precision statements for their test methods, so as
to incorporate at least a repeatability statement, the ILS Program is available to assist with the following
- Designing an Interlaboratory Study
- Identifying potential samples
- Soliciting volunteer laboratories
- Finding an available supplier
- Contracting with a distributor
- Reviewing laboratory instructions
- Reimbursing shipping expenses
- Collecting data
- Analyzing data
- Producing a draft precision statement
- Compiling information for the Research Report
- Recognition of participating labs
Once a Work Item has been registered (instructions here),
new programs should be registered
through the Interlaboratory Study (ILS) link in the My Tools section of the member's MyASTM page, available
after logging into ASTM's website.
Interlaboratory Study (ILS) Process
- Work Item - register a work item (if you have not done so already).
- Registration - register the ILS through the MyASTM area of the
- Conference Call - The Technical Contact (TC) will be contacted by
set up a
conference call to discuss the ILS. During this call the TC should be prepared to discuss the following
information: test specimens, lab supplies, potential suppliers, a distributor, a potential list of labs,
and what data should be collected as part of the study.
- Samples - if assistance is needed with finding and/or ordering
to be tested,
ASTM can provide support.
- Sample Funding - ASTM has funds available to assist with purchasing
preparation and shipping. After a proposal of costs is developed, ASTM will work with the committee to
determine how much assistance can be provided.
- Lab Solicitation - if there are not enough labs to do the testing,
can send out a
solicitation to the committee looking for volunteers.
- Lab Instructions - the study instructions should be developed and
samples are distributed. Please send them to ASTM for review.
- Data Report Forms - ASTM will collect the study data using an online
or an excel data report form (depending on the amount/complexity of the data). The data report form will
be sent to the technical contact for review before the labs receive it.
- Sample Distribution - once the study materials have been purchased,
to send them to a distributor for final prep and packaging (may be the same as the supplier).The
distributor will then ship the samples. ASTM will send the data report forms and the study instructions
to the labs.
- Data Submission - ASTM will track data submitted by the lab
- Statistical Summary - once all of the data has been received from the
labs, ASTM will
then compute the repeatability and reproducibility using ASTM Statistical Software. A draft precision
and bias statement will be written and sent to the TC for review.
- Research Report (RR) - to generate the RR, ASTM will utilize
during the ILS, including information in the online registration, study instructions, data analysis and
the precision and bias statement. The draft research report will be sent to the TC for review.
- Precision and Bias Statement - the precision and bias statement
with any other
revisions to the standard) should be placed on the next ballot.
- Approval - after the ballot is approved and the research report is
complete, ASTM will
assign a RR#, and send out copies of the RR to the TC and the participating labs.
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Precision and Bias
Additional Information: Ruggedness Testing; Pilot Testing
There are two measurements that serve to express precision in the evaluation of a standard test method. They
are commonly referred to as "repeatability" and "reproducibility" and provide the boundaries between which
- Repeatability - addresses variability between independent test results
within a single laboratory (otherwise known as intralaboratory testing).
- Reproducibility - addresses variability among single test results gathered
different laboratories (otherwise known as interlaboratory testing).
Bias, on the other hand, is defined as a systematic error that contributes to the difference between the mean
of a large number of test results and an accepted reference value. When included in a standard test method,
this statement describes the bias and the methods utilized to provide corrected test results. It is
important to remember that if an accepted reference value is not available, then the bias cannot be
established. However, if the bias is unknown but the direction or bounds of the bias can be estimated, this
information should be included in the bias statement.
As precision and bias are mandatory sections of an ASTM standard test method (per Section
A.21 Form and Style for ASTM Standards), the utmost care should be taken to ensure that the final
data, as well as the steps that were taken to generate the data, are as precise and accurate as possible. A
standard test method that is incapable of doing what it purports can be misleading. Precision and bias
statements strengthen the perceived validity of the standard test method and provide the user of the
document with the added confidence of knowing that the standard test method has been laboratory tested.
Precision and Bias Template
Repeatability Precision Template
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ASTM has published approximately 6000 test methods to date, with more being approved every day. The backbone
of many of these standard test methods is a comprehensive interlaboratory study that supports the Precision
and Bias statement. When an interlaboratory study is completed, it is very important to document the details
in a research report. A research report should contain a list of participating laboratories, description of
samples, a copy of the laboratory instructions, the equipment/apparatus used, a copy of the raw data, a
statistical summary and a copy of the precision and bias statement. The ASTM Form and Style
Manual (Section A29.1) states, "Where numerical data have been generated to establish the precision
and bias of a test method, a research report is required". To this end, we have developed a consistent
format in the ASTM Research Report
Template for you to use.
- ILS can assist with the following research report tasks:
- Answer any research report inquiries
- Create research reports from ILS studies
- Reformat older research reports to fit the ASTM research report Template
- Assign research report numbers
- A research report number will be assigned by ASTM when all of the following have been
- The research report is submitted to ILS
- It is reviewed for completeness
- The ballot item to include the corresponding precision and bias statement is
The published standard test method will include the research report number in a footnote to the Precision and
Bias section. To obtain a copy of a research report, contact ASTM Customer Service by phone
at 610-832-9585 (8:30 a.m. - 4:30 p.m. Eastern U.S. Standard Time, Monday through Friday) or by email at firstname.lastname@example.org.
For assistance with research reports, please contact email@example.com.
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