At the ICUMSA meeting in Atlanta (2004) the topic "Method numbering system" was on the agenda of Subject 3 and I participated in the discussions. I would like to continue this discussion with an analysis of the Method numbering system:
Method filing system
ICUMSA has a two-dimensional Method filing system in the Methods book, with GS sections and Methods inside the sections. A Method like GS1/2/3/4/7/8-23 (pH), serving as an example with a rather complex number, will be put to section GS1 as a single copy. All the other General Subjects, like GS2, GS3, GS4, GS7 and GS8, have to refer to section GS1, as they have no extra copies. If somebody wants to measure pH of raw sugar, s/he will find Method GS1/2/3/4/7/8-23 directly in section GS1. In case of other samples (e.g. thick juice) the Method will be found by a cross-reference rather than by "/8" included to the Method number. Thus the short "Filing number" or "identification number" or "ID number" GS1-23 would meet the needs of all readers of the Methods book.
Advantage of ID numbers
A use of ID numbers would result in more uniformity, instead of frequent changes of "Full numbers" after introduction of a Method to a new General Subject or a drop of a Method in one of the General Subjects. If the present “slash system” is kept, the numbers will not be constant, as expected by Lescure, Schäffler and Kunz in the discussion remarks in Atlanta ("... we should keep it as it is").
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I give some examples: |
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If white sugar Methods or raw sugar Methods can be used for PWS too, all these Method numbers would be altered in the near future by adding "/9". If organisations have already adopted the old Full number, ICUMSA must get in touch with them and ask to add "/9". Companies must correct their QA documents too. I believe that no additional "/9" is necessary, if cross-references are included in section GS9, but this would be the first break with the "slash tradition". The scope of all Method descriptions, quoted via "see... " in GS9, could be completed for PWS on the next opportunity. On the other hand, all special PWS Methods should be numbered like GS9-1, GS9-2 etc from the beginning. |
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Method GS1/2/3/4/7/8-23 (pH) is tentative for white sugar and from results given in ICUMSA Proc. 1986, pp. 426-429, I believe that no satisfying reproducibility will be found for white sugar in future collaborative studies. Therefore the tentative status will probably be dropped. This will cause a change of the Method number from GS1/2/3/4/7/8-23 to GS1/3/4/7/8-23 and with the "slash system" all cross references in GS3, GS4, GS7 and GS8 as well as the list of contributors have to be changed. With a Method number GS1-23, only a deletion of the cross reference in GS2 and an alteration of the Method description itself is necessary. A use of short ID numbers would show more uniformity than the present "slash system". |
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If more than one Method exists for a combination of sample and component, the Method used has to be indicated, according to Subject 3. If laboratories can use the ID number (like GS1-1 instead of the longer GS1/2/3-1), this may cause fewer misprints and users could be even happier with the short number, which is additionally easier for oral communication in different languages. |
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A step by step procedure |
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A modification could be done step by step, without abandoning the "slash system" in one go: |
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The sub-indices after the book dividers already refer to the short ID numbers. Therefore - after a possible drop of the white sugar pH Method - nothing has to be done in the sections GS3, GS4, GS7 and GS8. This is the first administrative advantage, and consistency is an advantage for book readers too. |
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The next step could be a definition of a Full number and an ID number in the Methods book. A Full number is an ID number like "GS1-13" with additional information like "/3/4/7/8". Even if Full numbers and ID numbers are used in parallel, no confusion is possible, because the "slash digits" of the Full numbers are not necessary for identification (if ICUMSA would start to have Methods like GS1/2/3-13 and GS1/3/4/7/8-13 in parallel, the "slash digits" would become part of the ID).
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All the contributing authors wrote Method descriptions which were given to one GS-section in the book. Why should their Methods not be quoted via the short ID number in the list of contributors? Future corrections would then only be necessary in case of new Methods or after moving a Method from one GS section to another (e.g. colour with MOPS buffer). With the present Full number references, any change of status of any Method in any new GS section will have effect even on the list of contributors. |
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If the ID number were be used in the footer of reprinted Method descriptions, this would be easier for readers. It is not possible to check a number like GS1/2/3/4/7/8-23 in the footer quickly during turning of pages.
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The use of Full numbers in the main index of the Methods book is bad for its readability. ID numbers could be used there as the next step.
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To change the Method number in the title of Methods is a serious step. If ID numbers shall be used for new Methods and the Full numbers shall be kept additionally, the scope of a Method description (example from GS1) could read as follows: "The Method is applicable to all raw sugars (General Subject 1), white sugars and speciality sugars requiring clarification (General Subjects 2 and 3). The Full number of the Method is GS1/2/3-1." |
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During the discussion in Atlanta, Kulkarni proposed to add T, O, A as a status information to the Method number. This must be done for every GS separately, because the status is often different. For the pH Method a Full number would then read as complex as follows: GS1,O/2,T/3,O/4,O/7,O/8,O-23. A confusion of O with zero is possible. Instead of this, I propose a status table given in the Methods book, showing for every ID number the relevant General Subjects as well as the status for these Subjects. The following table is given for the first 15 Methods, as an example: |