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KCDB FAQs
I. What is the KCDB and who uses it?

II. What kind of electronic files may I find in the KCDB?

III. How can I find comparisons or CMCs in the KCDB?

IV. The acronym or the full name of my NMI has changed: how it this dealt with in the KCDB?

V. What is a “KCDB absolute URL address”?

VI. Where can I find information about Pilot Studies?

VII. How can I publish the Final Report of a comparison in the Metrologia Technical Supplement?

VIII. How can I get statistics on the content of the KCDB?

IX. Example of the use of the KCDB text-free search engine: how can I make a diagram of the distribution of key comparisons according to their originating RMOs?

X. Where can I find EXCEL files of CMCs?



I. What is the KCDB and who uses it?
The KCDB is the essential resource for people needing information about measurement services.
1. The KCDB - the BIPM key comparison database - is a public website containing all information relating to the CIPM MRA, an arrangement establishing the equivalence of measurements made by, and certificates issued by, all the participating institutes (signatory National Metrology Institutes and other designated institutes).
2. The KCDB comprises two main sections: one contains information about the internationally recognized Calibration and Measurement Capabilities (CMCs) of the participating institutes, and another contains information about the key and supplementary comparisons supporting these CMCs.
3. Interested users such as industrialists can use the “CMCs” section to identify appropriate providers for any calibration service.
4. Participating institutes can compare their performance in key and supplementary comparisons.
5. Accreditors and regulators can find information supporting the uncertainty claims of accredited laboratories.
6. The information in the KCDB passes through a strict peer-review process. Submitted CMCs are peer-reviewed by the Regional Metrology Organizations (RMOs) in an intra- then inter-RMO process, and are published after approval by the Joint Committee of the Regional Metrology Organizations and the BIPM (JCRB). Final Reports of completed comparisons are published after approval by the relevant organizing body.
7. A special restricted-access website - the restricted-access JCRB CMC website - is used by the experts involved in the CMC peer-review process (username and password should be requested from the JCRB Executive Secretary: jcrb_es@bipm.org).

II. What kind of electronic files may I find in the KCDB?
Only PDF files.
1. The KCDB is a public website. It displays web pages with hyperlinks, including links to PDF files.
2. The PDF files posted in the KCDB are mainly Final Reports of comparisons, Technical Protocols of comparisons, and PDF files of CMCs.
  • Final Reports of key and supplementary comparisons are posted in the KCDB website once they have been approved by the appropriate body: a Consultative Committee (CC) or a Regional Metrology Organization (RMO).
  • Technical Protocols of comparisons are currently posted for comparisons in some fields of metrology, for instance “photometry and radiometry”. This could be extended to all metrology areas in the future.
  • The responsible person - usually the Contact Person in the Pilot laboratory, the CC Executive Secretary, or the Chairman of the appropriate Working Group - provides the KCDB Office with approved Final Reports and approved Technical Protocols. These files must be converted into PDF format before their transfer to the KCDB Office.
  • 3. The PDF files of CMCs are presented as one per country and per metrology area in Physics, or one per country and per category in Chemistry. They are compiled by the KCDB Office. They include a date, the mention “The BIPM key comparison database”, the mention “Calibration and Measurement Capabilities”, and the KCDB Logo.
    4. The KCDB website gives links to various other PDF files of informative nature, including a number of documents related to the CIPM MRA, the Summary Results of key comparisons, the Classification of Services used to draw up CMC files, and statistics on the content of the KCDB.
    5. No EXCEL or Word files are posted in the KCDB.

    III. How can I find comparisons or CMCs in the KCDB?
    By using the search engines that are proposed.
    1. The part of the KCDB on “Key and supplementary comparisons” proposes three different search engines: a free-text search engine, which is particularly efficient when one enters a word, for instance “accelerometer” (see IX); a search by comparison identifier (in part or in full), for instance “cr-51”; and a directed advanced search, which is particularly efficient for a search by category, for instance “Mass – Viscosity – COOMET”
    2. The part of the KCDB on “Calibration and Measurement Capabilities” proposes two different choices: a free-text search engine, which searches the whole CMC database independently of the metrology area; and a series of search forms, each designed for one specific metrology area. Each of these search forms provides direct access to PDF files of CMCs, and offers an advanced search facility based on the Classification of Services drawn up for the chosen metrology area.
    3. Note that the advanced search facilities for CMCs can be used from top to bottom (choose first a “Branch”, then a “Service”, then a “Sub-Service”), or laterally (direct choice of a “Sub-Service” in the complete list provided for the chosen metrology area). For instance, in the field of Length, choosing “Diameter standards” as a “Sub-Service” automatically selects the Branch “Dimensional metrology” and the Service “Linear dimensions”.

    IV. The acronym or the full name of my NMI has changed: how it this dealt with in the KCDB?
    The old acronym/name disappears from the “CMCs” part of the KCDB.
    1. Once the Director of the BIPM receives a formal letter informing him of the change in name or acronym of a National Metrology Institute or other designated institute participating in the CIPM MRA, the KCDB Office makes the appropriate changes in the KCDB.
    2. The old acronym and/or old full name of the laboratory disappear from the part of the KCDB website on “Calibration and Measurement Capabilities” (PDF files of CMCs and web pages displaying the CMCs).
    3. The old acronym and/or old full name are kept in the part of the KCDB website on “Key and supplementary comparisons”, particularly in the lists of participants in comparisons, but a note is inserted stating the new acronym and/or new full name, and the date of the change. When new results are approved, and for new comparisons to be registered, the new acronym and/or new full name are used.
    4. It is clear that the treatment is different for CMCs and for comparisons. This is because CMC part of the KCDB presents the up-to-date picture, whereas the Final Reports of comparisons present the information at the time the comparison took place.
    5. Note: The old acronym and/or old name of the laboratory may also remain in the restricted-access EXCEL files of CMCs, available via the JCRB CMC website, but only in the columns that are normally not imported into the KCDB (the “blue columns” containing additional information for the reviewers).

    V. What is a “KCDB absolute URL address”?
    An immediate way to get the up-to-date information on something you are interested in and that evolves with time.
    1. All URL addresses available from the KCDB are absolute, which means that any kind of information obtained from one of the directed search engines proposed by the KCDB system is returned through a unique and permanent web address.
    2. This unique web address can be bookmarked or copy/pasted into any kind of document (PDF file, Word file, e-mail, etc.).
    3. When one clicks on one of these bookmarked web addresses, one obtains the most up-to-date information corresponding to the items that were initially chosen in the directed search engine.
    4. 1st example. The URL address http://kcdb.bipm.org/appendixC/L/EG/L_EG.pdf is the unique and permanent address that returns the PDF file listing all CMCs in Length declared by Egypt and published in the KCDB, whatever their numbers, uncertainties, ranges, etc..
    5. 2nd example. The URL address http://kcdb.bipm.org/appendixC/country_list_search.asp?CountSelected=CA&sservice=M/FF.9.2 is the unique and permanent address that returns the web page of CMCs related to “Volume gas flow rate” declared by Canada and published in the KCDB, whatever their numbers, uncertainties, ranges, etc. Note that in both these examples, the URL address is constructed in a relatively simple way.
    6. 3rd example. By clicking here, one obtains the current graph of equivalence for the measurement of the mass fraction of aluminium in silicon nitride powder in key comparison CCQM-K58.

    VI. Where can I find information about Pilot Studies?
    Pilot Studies are not registered in the KCDB; please refer to the CC pages on the BIPM website.
    1. The comparisons registered in the KCDB are the key and supplementary comparisons conducted by the Consultative Committees, the BIPM and the RMOs within the framework of the CIPM MRA.
    2. Pilot Studies are not registered in the KCDB.
    3. Information about Pilot Studies in Chemistry can be found on the BIPM website (click here).

    VII. How can I publish the Final Report of a comparison in the Metrologia Technical Supplement?
    Send the approved Final Report to the KCDB Office.
    1. A Metrologia Technical Supplement abstract provides a formal citeable reference for Final Reports posted in the KCDB. All Final Reports are peer-reviewed before their publication in the KCDB, and the Technical Supplement entry includes the name of the approving body.
    2. Once the Final Report of a key or supplementary comparison has been approved and posted in the KCDB, it is automatically published in the Metrologia Technical Supplement (unless the authors do not wish it). A short abstract in Word format is required, and the publication process is handled by the KCDB Office.
    3. The Metrologia Technical Supplement abstract is generally online within a few days of publication of the Final Report.
    4. The Technical Supplement of Metrologia is available from the Metrologia website (click here).
    5. Note: The Final Report of a Pilot Study may also be published in the Metrologia Technical Supplement, but this process is handled by the CC Executive Secretary rather than the KCDB Office.

    VIII. How can I get statistics on the content of the KCDB?
    From the KCDB Statistics page.
    1. Statistics on the content of the KCDB are prepared by the KCDB Office and are available on-line from the KCDB Statistics page. This includes the number of key and supplementary comparisons (updated in real time), and PDF files showing the participation in key and supplementary comparisons (updated every six months, at the issue of each new KCDB Newsletter) and the number of CMCs by metrology area and by country (updated in real time).
    2. The KCDB Office provides on demand an additional EXCEL file containing the information on key and supplementary comparisons registered in the KCDB, as a snapshot of the content of the database valid at a given date. This makes it possible to carry out statistical analyses using EXCEL functions or customized macro-functions. The file is compiled by the BIPM, using an SQL request named “Angela”. The delivery time is about two working days.
    3. The text-free search engine, which is implemented on the two parts of the KCDB website, provides a convenient means of analysing the content of the databases in terms of numbers, provided one uses the links proposed on the left of the screen to refine the search (see the example below).
    4. The EXCEL files that are used to generate the PDF files displayed in the KCDB Statistics page are available from the access-restricted JCRB CMC website (link “KCDB statistics”). Note that these EXCEL files track the changes and their dates, and thus allow some recollection of the history of the KCDB. In addition, many numbers that are not shown in the PDF files of statistics are included in the EXCEL files. All this information makes it possible to compile any graphs of interest.

    IX. Example of the use of the KCDB text-free search engine: how can I make a diagram of the distribution of key comparisons according to their originating RMOs?
    Enter “key” and refine using the links provided on the left of the screen.
    1. Enter “key” in the box of the free-text search engine implemented on the part “Key and supplementary comparisons” of the KCDB website.
    2. One obtains the total number and the full list of key comparisons registered in the KCDB, plus a number of links on the left showing the metrology areas, the statuses, and the conducting organizations, with the corresponding numbers given in parentheses.
    3. All the links proposed in this left-hand menu are clickable in two ways: either to select an item, or to exclude an item (the little hand cursor indicates where to click either to select or to exclude).
    4. Selecting one item, or excluding one or several item(s), rapidly allows the search to be refined and thus reduces the number of responses. For instance, excluding all CCs and the BIPM from the box “Organizations” gives the statistics according to the metrology area and the status of the ensemble of RMO key comparisons.
    5. By clicking again on the link one has just selected, or excluded, allows one to return to the previous step.

    X. Where can I find EXCEL files of CMCs?
    In the restricted-access JCRB CMC website.
    1. CMCs are submitted for peer review in the form of EXCEL files, but they are not published in this form in the KCDB.
    2. Once the CMCs have been approved by the JCRB, the KCDB Office imports the CMCs into the KCDB.
    3. Templates of EXCEL files to be used for submitting CMCs to the intra- and inter-RMO review process are available, together with guidelines, from the CIPM MRA documents page on the BIPM website.
    4. EXCEL files of CMCs to be reviewed by the RMOs are available from the access-restricted JCRB CMC website (links “Complete list of CMCs” or “CMCs by metrology area”, for instance “AUV”, provided on the left).
    5. Once the CMCs have been published in the KCDB, the corresponding EXCEL files are available from the access-restricted JCRB CMC website (link “Get Published CMCs”). The EXCEL files of CMCs are presented as one per country and per metrology area in Physics, or one per country and per category in Chemistry. They are compiled by the KCDB Office from the approved CMC files.
    6. The EXCEL files of CMCs which are made available from the “Get Published CMCs” part of the access-restricted JCRB CMC website, contain the data currently displayed in the KCDB, and are thus the files that must be used in case of further modifications (see document CIPM MRA-D-04).
    7. The EXCEL files of CMCs which are made available from the “Get Published CMCs” include those CMCs that are temporarily removed (“greyed-out”) from the database because, for instance, of lack of a approved QS, although these greyed-out CMCs are not displayed in the KCDB website.
    8. Username and password to access the restricted-access JCRB CMC website should be requested from the JCRB Executive Secretary: jcrb_es@bipm.org).