What is the difference between inter laboratory comparison and round robin testing?
Interlaboratory Testing Programs (ILTPs) (i.e. Interlaboratory
Comparisons) are similar in intent to round robin tests; both are a
type of proficiency testing. Both attempt to increase the
understanding of the precision and influence factors for the
analytical tests being performed along with the performance of the
laboratories (personnel and facilities) that do the tests. This
will hopefully improve the quality of the analyses performed.
ILTPs are typically run by an unbiased party, with identical
samples sent out for analysis to multiple labs. The test results
are sent in to the party running the ILTP which blinds the data
(hides which test result comes from which lab), performs a review
of the data and returns a report to the participants. In most cases
the participant only knows their individual result.
Round-robin testing is typically arranged by one of the
participants and involves sending the same or identical samples to
several labs (more than 4 or 5 labs is unusual). The participants
are often different sites for the same company or labs in one
geographical region. All participants may be aware of each other's
test results. A formal report is not necessarily prepared.
In summary,
ILTPs involve a greater number of more diverse participants than
RRs.
ILTP organizers are independent of participants whereas RR
organizers may be participants.
ILTP results are blinded whereas RR results may not be.
ILTPs results are formally analyzed and documented whereas RR
results may not be.
ILTP results (In ASTM terms - Interlaboratory Study or ILS) may
be sufficient to prepare a statistical precision statement for an
industry standard test method whereas RR results cannot typically
be used for establishing a test method precision.
ILTPs are likely to detect common faults whereas the limited
number and diversity of participants in RRs may not.
Another term for ILTP is Interlaboratory Crosscheck Program.
Note that industry usage of these terms is not precise and that
they may be used interchangeably.
(Roy Meyer, Lead Measurement Specialist for a major oil
company)
