Mutual recognition of national measurement standards and of cal-
ibration and measurement certificates issued by national metrol-
The essential points
The Mutual Recognition Arrangement (MRA) has been drawn up by t-
he International Committee of weights and Measures (CIPM), under
the authority given to it in the Metre Convention, for signature
by directors of the national metrology institutes (NMIs) of Mem-
ber States of the Convention.
．to establish the degree of equivalence of national measurement
standards maintained by NMIs;
．to provide for the mutual recognition of calibration and meas-
urement certificates issued by NMIs;
．thereby to provide governments and other parties with a secure
technical foundation for wider agreements related to internat-
ional trade, commerce and regulatory affairs.
．international comparsions of measurements, to be known as key
．supplementary international comparisions of measurements;
．quality systems and demonstrations of competecnce by NMIs.
．statements of the measurement caopabilities of each NMI in a
database maintained by the BIPM and publicly available on the
NMI directors sign the MRA with the approval of the appropriate
authorities in their own country and thereby:
．aocept the process specified in the MRA for establishing the
．recognize the results of key and supplementary comparisions as
stated in the database;
．recognize the calibration and measurement capabilities of oth-
er participating NMIs as stated in the database.
．signature of the MRA engages NMIs but not necessarily any oth-
er agency in their country;
．responsibility for the results of calibrations and measuremen-
ts rests wholly with the NMI that makes them and is not, thro-
ugh the MRA, extended to any other participating NMI.
．overall coordination is by the BIPM under the authority of the
CIPM, which is itself under the authority of the Member States
of the Metre Convention;
．the Consultative Committees of the CIPM, the Regional Metrolo-
gy Organizations and the BIPM are responsible for carrying out
the key and supplementary comparisons;
．a Joint Committee of the Regional Metrology Organizations and
the BIPM is responsible for analysing and transmitting entries
into the database for the calibration and measurement capabil-
ities declared by the NMIs.
National accreditation and regulatory bodies require multilater-
al agreements or arrangements to define the conditions under wh-
ich they can accept calibration, measurement and test certifica-
tes issued by laboratories accredited in other countries. These
agreements or arrangements depend for their validity on the ac-
curacy of national mesurement standards and of calibration and
measurement certificates issued by national metrology institut-
This arrangement provides for the mutual recognition of nationa-
l mesaurement standards and of calibration and measurement cert-
ificates issued by national metrology institutes, and is founded
on the efforts of each individual national metrology institute
to base its measurements and measurement uncertainties on SI un-
To put the criteria for mutual recognition on an objective foot-
hing, the arrangement calls upon: (a) the results of a set of k-
ey comparisons carried out using specified procedures which lead
to a quantitative measure of the dagree of equivalence of natio-
nal measurement standards; (b) the operation by each NMI of a s-
uitable way of assuring quality; and (c) successful participati-
on by each NMI in appropriate supplementary comparisons. Togeth-
er, these three procedures demonstrate to participating institu-
tions the degree to which each may have confidence in the resul-
ts reported by others, and so promote mutual confidence between
For the purposes of this arrangement, the degree of equivalence
of measurement standards is taken to mean the degree to which t-
hese standards are consistent with reference values determined
from the key comparisons and hence are consistent with one anot-
her. Each reference value is referred to as a key comparison re-
ference value and, in most cases, it can be considered to be a
close, but not necessarily the best, approximation to the SI va-
lue. The degree of equivalence of a national measurement standa-
rd is expressed quantitatively in terms of its deviation from t-
he key comparison reference value and the uncertainty of this d-
This arrangement is in two parts: through part one, signatories
recognize the degree of equivalence of national measurement sta-
ndards of participating national metrology institutes; through
part two, the signatories recognize the validity of calibration
and measurement certificates issued by participating institutes.
Formally, this document is a technical arrangement among direct-
ors of the national metrology institutes of Member States of the
Metre Convention and it is not a diplomatic treaty. It is drawn
up by the CIPM under the Metre Convention and it is neither an
extension to the Convention nor a replacement of any Article of
the convention. The directors who in due course decide to sign
the arrangement do so with the approval of the appropriate gove-
nmental or other offical authorities in their own country. It is
expected that participation in this arrangement will open the w-
ay to, and provide the technical basis for, wider agreements re-
lated to trade, commerce and regulatory affairs, signed by the
competent authorities in each country or region.
Participation in the arrangement through their regional metrolo-
gy organization is also open to the NMIs of States and Economies
that are Associates of the CGPM.
1 The arrangement
1.1 This is an arrangement between national metrology institutes
which specifies terms for the mutual recognition of national
measurement standards and for recognition of the validity of
calibration and measurement certificates issued by national
metrology imstitutes. It is drawn up by the CIPM with the a-
uthority given it under Article 10 (1921) of the Rules Anne-
xed to the Metre Convention.
1.2 this arrangement is in two parts as specified in paragraph 2
below:part one concerns national measurement standards and
part two concerns calibration and measurement certificates.
1.3 Participation national metrology institutes, signatories to
this arrangement, may choose to limit their participation to
part one, the recognition of national measurement standards.
1.4 each signatory to this arrangement is the national metrology
institute designated by the appropriate national government-
al or other offical authority of the Member State of the Me-
tre Convention as being responsible for national measurement
standards. For any state that has more than one such design-
ated institute, the arrangement is signed by one institute
on behalf of all, the names of the other institutes being a-
ttached to the document.
1.5 Designated NMIs of States or Economies that are Associates
of the CGPM may participate in the arrangement only through
their regional metrology organizations by signing a declara-
tion, appended to this arrangement.
1.6 Intergovernmental and international organizations designated
by the CIPM may also participate in the arrangement.
2 Scope of the arrangement
2.1 participating national metrology institutes, listed in Appe-
ndix A, recognize the degree of equivalence of national mea-
surement standards, dervied from the results of key compari-
sons, for the quantities and values specified in Appendix B.
This constitutes part one of the arrangement.
2.2 Participating institutes recognize the validity of calibrat-
ion and measurement certificates issued by other participat-
ing institutes for the quantities and ranges specified in A-
ppendix C.This constitutes part two of the arrangement.
3 Technical basis of the arrangement
3.1 The technical basis of this arrangement is the set of resul-
ts obtained in the course of time through key comparisons c-
arried out by the Consultative Committees of the CIPM, the
BIPM and the regional metrology organizations (RMOs), and p-
ublished by the BIPM and maintained in the key comparison d-
atabase. Detailed technical provisions are given in the Tec-
hnical Supplement to this arrangement.
3.2 Key comparisons carried out by Consultative committees or t-
he BIPM are referred to as CIPM key comparisons; key compar-
isons carried out by regional metrology organizations are r-
eferred to as RMO key comparisons; RMO key comparisons must
be linked to the corresponding CIPM key comparisons by means
of joint participants. The degree of equivalence derived fr-
om an RMO key comparison has the same status as that derived
from a CIPM key comparison.
3.3 A Joint Committee of the RMOs and the BIPM (the Joint commi-
ttee or JCRB), created by the CIPM, is responsible for the
coordination of data provided by the RMOs, and other actions
undertaken by them to promote confidence in calibration and
measurement certificates (see paragraph 9.3).
4 Responsibilities of the Consultative Committees of the CIPM
The Consultative Committees have the responsibility for choos-
ing the key comparisons listed in Appendix D and affirming the
validity of the results. The particular responsibilities of t-
he Cosultative Committees are detailed in the Technical Suppl-
5 Responsibilities of the regional metrology organizations
The national metrology institutes that are signatories to this
arrangement undertake to put in place appropriate strutures w-
ithin their RMOs so that the RMOs may:
a) make proposals to the Consultative Committees on the choice
of key comparisons;
b) carry out the RMO key comparisons, described in the Techni-
cal Supplement, corresponding to the CIPM key comparisons;
c) participate in the JCRB (see paragraphs 9.3 and 9.4 below);
d) carry out supplementary comparisons and other actions desi-
gned to support mutual confidence in the validity of calib-
ration and measurement certificates issued by participating
institutes (see paragrph 7.3 below).
6 Participation in key and supplementary comparisons
6.1 Participation in a CIPM key comparison is open to laborator-
ies having the highest technical competence and experience,
normally the member laboratories of the appropriate Consult-
ative Committee. Those laboratories that are not members of
a consultative committee and not NMIs must be nominated by
the designated national metrology institute referred to in
paragraph 1.4 as being responsible for the relevant national
measurement standards. In choosing participants, the Consul-
tative Committees should take proper account of regional re-
presentation. The number of laboratories participating in CI
PM key comparisons may be restricted for technical reasons.
6.2 Participation in key comparisons organized by an RMo is open
to all RMO members and to other institutes that meet the ru-
les of the regional organization (including institutes invi-
ted from outside the region) and that have technical compet-
ence appropriate to the particular comparsion.
6.3 Participation in RMO supplementary comparisons is open to t-
hose institutes meeting the requirements specified in pargr-
7 Confidence in measurements
7.1 Confidence in measurements is an essential prerequiste to
international trade and facilitates almost every task in the
industrialized world. To a large extent this confidence alr-
eady exists and is based on the SI, which is the cornerst o-
ne of the international measurement system, as realizsed by
the national metrology institutes. The function of this mut-
ual recognition arrangement is to extend and consolidate pre
-existing worldwide confidence in measurements.
7.2 Institutes participating in this arrangement are expected to
extend existing international confidence in teir activities
by publishing regular reports on the work of their laborato-
ries and transmitting them to the BIPM, by participation in
relevant conferences, and by taking part in the activities
organized by the BIPM.
7.3 In addition to participation in the key and supplementary c-
omparisons, identified in paragraph 6, recognition of calib-
ration and measurement certificates requires one of the fol-
lowing procedures in order to establish the necessary mutual
a) an NMI that chooses for its calibration and measurement
services a quality system that meets the requirements of
ISO Guide 25 or equivalent for an NMI, assessd by an acc-
reditation body fulfilling the requirements of ISO Guide
58, declares its calibration measurement capabilities (s-
ee paragraph T.7) and submits them to the local RMo for
review and transmission to the Joint Committee for analy-
sis and inclusion in Appendix C;
b) an NMI that chooses to use a different way of assuring q-
uality or chooses a different quality system, or ISO Gui-
de 25 without third - party assessment, for its calibrat-
ion and measurement service declares its calibration mea-
surement capabilities (see paragraph T.7) and submits th-
em to the local RMO for review and transmission to the J-
oint Committee for analysis and inclusion in Appendix C.
Demonstration of competence and capability may reuqire visi-
ts and examination of procedures by an NMI and/or by peers
selected by the local RMO.
7.4 Nothing in this arrangement is intended to limit the freedom
of one or more signatories to establish mutual recognition,
as specified in paragraphs 2.1 and 2.2, outside this arrang-
8 Disputes in the operation of the arrangement
This arrangement is operated by the BIPM in close consultation
with the Consultative committees and the RMOs whose responsib-
ility it is, under paragraphs 4 and 5 above, to carry out and
evaluate the results of the key comparisons. Disagreements th-
at arise in the operation of this arrangement are discussed f-
irst within the appropriate Consultative Committee, the RMO or
the Joint Committee and if not resolved there, are referred to
9.1 Overall coordination of activities related to this arrangem-
ent resides with the CIPM.
9.2 Coordination of the key comparisons is effected through con-
sultations between the Consultative Committees and the RMO's
9.3 Coordination of the supplementary comparisons and other act-
ions related to confidence in calibration and measurement c-
ertificates undertaken by the regional metrology organizati-
ons is carried out by the JCRB. The JCRB is created by the C
IPM comprising representatives of the RMOs and is chaired by
the Director of the BIPM, Its terms of reference are given
in Appendix E.
9.4 Under the overall responsbility of the CIPM, the Joint Comm-
ittee is responsible for analysing and maintaining the cont-
ent of Appendix C.
10 Responsibility and liability for measurements
10.1 It is recognized and accepted by each signatory that this
arrangement cregtes no rights, liabilities or obligations
that will have binding effects in national or international
10.2 It is recognized and accepted by each signatory that this
arrangement covers, in each country, only the signatory in-
stitute and other institutes represented by it It dose not
necessarilyextend to other metrological or regulatory bodi-
es in that country.
10.3 Rsponsbility for all measurements made under this arrangem-
ent rests wholly with the institute making the measurement-
s. No responsibility for declared uncertainties of statmen-
ts of quality is assumed by the CIPM, the BIPM, the Consul-
tative Committees or the RMOs.
11 Signing this mutual recognition arrangement and bringing it
11.1 The procedure for implementing this arrangement is as foll-
．at the meeting of directors of national metrology instit-
utes held on 23-25 February 1998, the directors were inv-
ited to initial a draft of this arrangement.
．at the meeting of directors of national metrology instit-
utes to be held at the time of the 21st CGPm in October 1
999, dircetors will be invited to sign this arrangment f-
or an initial period of four years.
New signatories may attach themselves to this arrangementat
any time by application to the Director of the BIPM.
11.2 To withdraw from the arrangement, the Director of a signat-
ory institute should notify the Director of the BIPM six m-
onths prior to the effectivee date of withdrawal. The Dire-
ctor of the BIPM will notifiy all other signatories of such
notice of withdrawal not later than one month after it has
11.3 during the period from October 1999 until such time as the
first round of key and supplementary comparisons has been
completed and the quality systems specified in paragraph 7.
3 put in place, the arrangement will operate in a transiti-
onal mode. Provisional degrees of equivalence (Appendix B)
will be based on the results of comparisons carried out si-
nce about 1988, reviewed and approved by the Consultative
committee for each filed and entered into the key comparis-
on database referred to in paragraph 3.1. Provisional cali-
bration Capabilities and measurement capbilities (Appendix-
C) will be based on corresponding data reviewed by the RM-
Os and analysed by the JCRB, taking into account the proc-
edures specified in paragraph 7.3 and included in the key
11.4 After the initial period of four years, signatiories may,
with the approval of the appropriate govenmental or other
official authorities in their own country, make changes to
this arrangement at meetings organized by the CIPM of dirc-
etors of the national metrology institutes.
12 Status of national measurement standards calibrated by the B-
IPM or by a national metrology institute
Nothing in this arrangement restricts the rights under the M-
etre Convention of participating national metrology institut-
es to have their national standards calibrated by the BIPM or
by another national metrology institute. The mutual recognit-
ion of such standards depends upon subsequent participation
in key or supplementary comparisons (see paragraphs 3 and 6
13 NMIs that are not members of an RMO
Those NMIs that wish to participate in this arrangement buy
are not members of an RMO, should either form a new RMO, or
for the purposes of this arrangement, associate themselves w-
ith an existing RMO, whichever is the more appropriate. If n-
either approach is possible, they should seek to make special
14 NMIs that are members of more than one RMO
Those NMIs that are members of more than one RMO must declare
with which RMO they will paricipate in part two of this arra-
15 Entry of new RMOs into the joint Committee
The entry of a new RMO into the Joint Committee is subject to
approval by the CIPM.
The technical basis for this arrangement is the set of resul-
ts obtained during the key comparisons carried out by the Co-
nsultative Committees, the BIPM and the RMOs (paragraph 3.1)
. The following specify conventions and responsibilites rela-
ting to the key comparisons.
T.1 CIPM key comparisons lead to reference values, known as
key comparison reference values.
T.2 For the purposes of this arrangement, the term degree of
equivalence of measurement standards is taken to mean the
degree to which a standard is consistent with the key co-
mparison reference value. The degree of equivalence of e-
ach national measurement standard is expressed quantitat-
ively by two terms: its deviation from the key comparison
reference value and the uncertainty of this deviation (at
a 95% level of confidence). The degree of equivalence be-
tween pairs of national measurement standards is express-
ed by the difference of their deviations from the refere-
nce value and the uncertainty of this difference (at a 95
% level of confidence).
T.3 Although a key comparison reference value is normally a
close approximation to the corresponding SI value, it is
possible that some of the values submitted by individual
participants may be even closer. In a few instances, for
example in some chemical measurements, there may be diff-
iculty in relating results to the SI. Nevertheless, the
key comparison reference value and deviations from it are
good indicators of the SI value. For this reason, these
values are used to express the degree of equivalence bet-
ween the standards of paricipating laboratories. In some
exceptional cases, a Consultative Committee may conclude
that for technical reasons a reference value for a parti-
cular key comparison is not appropriate; the results are
then expressed directly in terms of the degrees of equiv-
alence between pairs of standards.
T.4 The results of the RMO key comparisons are linked to key
comparison reference values established by CIPM key comp-
arisons by the common participation of some institutes in
both CIPM and RMO comparisons. The uncertainty with which
comparison data are propagated depends on the number of
institutes taking part in both comparisons and on the qu-
ality of the results reported by these institutes.
T.5 The results of the CIPM and the RMO key comparisons, the
key comparison reference values, the deviations from the
reference values and their uncertainties, together with
other information necessary for their interpretation, are
published by the BIPM and entered into the key comparison
T.6 CIPM and RMO key comparisons must be carried out followi-
ng the Guidelines for CIPM key comparisons published by
the BIPM and available on the BIPM Web page.
T.7 For calibration and measurement certificates, the quanti-
ties, ranges and calibration and measurement capabilities
expressed as an uncertainty (normally at a 95% level of
confidence but in some cases it may be at a higher, spec-
ified, level), are listed for each participating institu-
te in Appendix C. They must be consistent with the resul-
ts given in Appendix B, derived from the key comparisons.
If, as a result of a key comparison, a significant unres-
olved deviation from the key comparison reference value
persists for the standard of a particular participating
institute, the existence of this deviation is noted in A-
ppendix C. In this case, the institute has the choice of
either withdrawing from Appendix C one or more of the re-
levant calibration and measurement services or increasing
the corresponding uncertainties given in Appendix C. The
calibration and measurement capabilities listed in Appen-
dix C are analysed by the Joint Committee following the
procedures given in 7.3 above. The calibration and measu-
rement capabilities referred to in this paragraph are th-
ose that are ordinarily available to the customers of an
institute through its calibration and measurement servic-
es; they are sometimes referred to as best measurement c-
T.8 Responsibilities of the Consultative Committees: the Con-
sultative Committess have a prime role in choosing and i-
mplementing key comparisons and in affirming the validity
of the results. THeir particular responsibilities are:
a) to identify the key comparisons in each field and mai-
ntain a current list (Appendix D);
b) to initiate and organize, with the collaboration of t-
he BIPM, the execution of key comparisons at intervals
to be decided individually for each comparison;
c) to review the results of CIPM key comparisons and det-
ermine the reference values and degrees of equivalence
on the basis of the proposals of the appropriate work-
d) to approve the final report of CIPM key comparisons f-
or publication by the BIPM;
e) to examine and confirm the results of RMO key and sup-
plementary comparisons and incorporate them in Append-
ix B and key comparison database;
f) to examine and confirm the results of bilateral key c-
omparisons for entry into Appendix B and the key comp-
T.9 RMO key comparisons: the RMO key comparisons extend the
metrological equivalence established by the CIPM key com-
parisons to a greater number of national metrology insti-
tutes including those of States of Economies that are As-
sociates of the CGPM. Redundancy, coherence and timeline-
ss are important aspects of regional comparisons for they
ensure that the overall system of comparisons is robust.
Regional organizations therefore have a particular respo-
nsibility for ensuring that:
a) links with the CIPM key comparisons provide adequate
redundancy through the participation of a sufficient
number of laboratories in both sets of comparisons to
ensure that links to the key comparison reference val-
ues are established with acceptably low uncertainty;
b) the procedures used in regional comparisons, and the
evaluation of the results and uncertainties, are comp-
atible with those used in the CIPM key comparisons;
c) the timing of the RMO key comparisons is coordinated
with, and is at least as frequent as, those of the CI-
PM key comparisons;
d) the results of RMO key comparisions are carefully eva-
luated by the RMO, which also takes responsibility for
ensuring that the proper procedures have been followed
, and then the results are submitted for publication
and to the relevant CC for incorporation in Appendix B
and the key comparison database;
e) the results of appropriately performed bilateral comp-
arisons are considered and then submitted to the rele-
vant Consultative Committee for incorporation in Appe-
ndix B and the key comparison database;
f) in the case that an RMO key comparison takes place be-
fore the corresponding CIPM key comparison, the link
to the subsequent key comparison reference value is d-
eferred until both key comparisons are completed.
T.10 supplementary comparisons : in addition to the key compa-
risons, the Consultative Committees, the RMOs and the BI-
PM may carry out supplementary comparisons to meet speci-
fic needs not covered by key comparisons, including comp-
arisons to support confidence in calibration and measure-
The Joint Committee of the RMOs and the BIPM (see paragr-
aph 9.3 above) provides a forum for the coordination, am-
ong the regions, of the supplementary comparisons carried
out by the RMOs in order to bolster confidence in calibr-
ation and measurement certificates.
Appendices to the arrangement
Appendices A, B, C and D are maintained electronically in the k-
ey comparison database held at the BIPM. During the initial fou-
r-year period, the database (which was designed by the NIST) wi-
ll be held jointly by the BIPM and the NIST.
List for national metrology institutes that are signatories to
the arrangement, together with their logos.
B1: Results of CIPM key comparisons.
B2: Results of RMO key comparisons.
B3: Results of supplementary comparisons.
For each key comparison the following are included:
．individual values for each institute together with their decl-
．the key comparison reference value with its associated uncert-
．for each institute, the deviation from the key comparison ref-
erence value and the uncertainty in that deviation (at a 95%
level for confidence), i.e. its degree of equivalence;
．the degress of equivalence between the standards of each of t-
he participating institutes.
Quantities for which calibration and measurement certificates a-
re recognized by institutes participating in part two of the ag-
reement. The qUantities, ranges and calibration and measurement
capabilities expressed as an uncertainty (normally at a 95% lev-
el of confidence) are listed for each participating institute.
List of key comparisons.
Terms of reference of the Joint Committee of the Regional Metro-
logy Organizations and the BIPM (JCRB).
Glossary of terms used in this arrangement
BIPM:Bureau International des Poids et Mesures.
CGPM:General Conference of Weights and Measures.
CIPM:International Committee of Weights and Measures.
Calibration and measurement capability:the highest level of cal-
ibration or measurement normally offered to clients, expressed
in terms of a confidence level of 95%, sometimes referred to as
best measurement capability.
Calibration or measurement certificate: a certificate issued by
a national metrology institute and relating to a test, calibrat-
ion or measurement of an instrument or a reference material (pe-
rtaining either to physical or to chemical measurements).
CIPM key comparison: a key comparison executed by a Consultative
Committee or the BIPM leading to a key comparison reference val-
Degree of equivalence of a measurement standard: the degree to
which the value fo a measurement standard is consistent with the
key comparison reference value. This is expressed quantitatively
by the deviation from the key comparison reference value and the
uncertainty of this deviation. The degree of equivalence between
two measurement standards is expressed as the difference between
their respective deviations from the key comparison reference v-
alue and the uncertainty of this difference.
Key comparison: one of the set of comparisons selected by a Con-
sultative Committee to test the principal techniques and methods
in the field (note that key comparisons may include comparisons
of representations of multiples and sub-multiples of SI base and
derived units and comparisons of artefacts).
Key comparison database: the database maintained by the BIPM wh-
ich contains Appendices A, B, C and D of this Mutual Recognition
Key comparison reference value: the reference value accompanied
by its uncertainty resulting from a CIPM key comparison.
National metrology institute: the national metrology institute
signatory to this arrangement is the metrology institute design-
ated by the appropriate national governmental or other official
authority as that responsible for national measurement standard-
RMO key comparison: a key comparison executed by an RMO. Note:
only key comparisons carried out by a Consultative Committee or
the BIPM lead to a key comparison reference value. For a key co-
mparison carried out by a regional metrology organization the l-
ink to the key comparison reference value is obtained by refere-
nce to the results from those institutes which have also taken
part in CiPM key comparison.
Supplementary comparison: comparisons carried out by the Consul-
tative Committees, the RMOs and the BIPM to meet specific needs
not covered by key comparisons, including comparisons to support
confidence in calibration and measurement certificates.
Terms of reference of the joint Committee of the Regional Metro-
logy Organizations (RMOs) and the BIPM.
1 The joint Committee is charged with
a) Coordinating the activities among the RMOs in establishing
confidence for the recognition of calibration and measurem-
ent cerificates, according to the terms of the Mutual Reco-
gnition Arrangement (MRA);
b) making policy suggestions to the RMOs and to the CIPM on t-
he operation of the MRA;
c) analysing the application by each RMO of the criteria of t-
d) analysing and entering into Appendix Cthe proposals of each
RMO in respect of the calibration and measurement capabili-
ties of their member NMIs and reporting to the CIPM;
e) facilitating appropriate inter-regional supplementary comp-
f) writing an annual report on the activities of the Joint Co-
mmittee to the CIPM and to the signatories of the MRA.
2 Membership and meetings of the joint Committee
a) each RMO informs the Director of the BIPM of the name of i-
ts official representative on the Joint Committee;
b) at each meeting of the Joint Committee the representatives
may be accompanied by appropriate advisors;
c) the Joint Committee operates by consensus;
d) the Joint Committee should meet at least once a year.