THE SCIENCE OF THE FILING ENGINEERThe Simplex Alpabetic Method Is Considered the Most Efficient and Takes Care ofTAverage Requirements - It May Be the 95% File-Complex Methods Also Explained
Butters, Roland W. 1921. “The Science of the Filing Engineer.” Filing & Office Management 6(7): 193–94. https://www.google.com/books/edition/Filing_Office_Management/o1rnAAAAMAAJ?hl=en&gbpv=1&pg=PA193&printsec=frontcover&dq=duplex.
Also, many exponents of filing knowledge have saidthat their file is a "fool-proof" one. I believe that youquestion this statement, as the only way to have afile as near perfect as possible, is to have safe andsane ideas and put them into practice; that is whythe Alphabetic file is the 95% file.
Alphabetic filing accounts for 95% of filing systems according to Butters.
The reason for this beingin the Complex classification is, as one will tell youwho has operated a Subject File, because a great dealof care must be exercised in not only laying out theproper plan, but working in and cooperating withthose who send matter to be filed, and are constantlyasking for it. The file clerk may think it goes in oneplace, but unless it is carefully marked as to whereit should be filed and then remembered, and possiblyagain classified by card, it is many times found a dif-ficult matter to handle.
The next Complex method in order, is the Numeric,which may be divided into three classes, straight num-eric, duplex and decimal. It is safe to say that withthe straight Alphabetic or Geographic, ninety-five per-cent of the cases where an Index is used will be moreefficiently handled by the use of either one of theseMethods, than by the Numeric. However, there aresome cases where there is a great deal of cross refer-ence, thus making the use of the Numeric methodmore advantageous.
This is likely the reason why most commonplacers using index card systems use alphabetic set ups by subject rather than Niklas Luhmann's duplex numeric variation.
DUPLEX NUMERIC SYSTEM.
McCord, James Newton. 1920. A Textbook of Filing. D. Appleton. https://www.google.com/books/edition/A_Textbook_of_Filing/SBowAAAAYAAJ?hl=en&gbpv=0.
The material filedcan be arranged as the cards would be,so as to bring together all the paperson a given subject.
is essential in subject work becausesome subjects are closely related andyet not sufficiently so to be filed to-gether.
The use of the cross reference sheet
A portion of the reason why Luhmann chose a duplex numeric filing system for his zettelkasten.
secondary number form of notation be considered in perfect order with-e. g.Administration :1-1-a General1-2-a Officers1-2-b Meetings of officers .This allows for more expansion and iscommonly termed "Duplex Numeric."
The numeric arrangement elim-inates the decimal feature and is used when the number of main divisions is likely to exceed nine, a primary and
This is exactly Niklas Luhamann's zettelkasten numbering system.
The object of any system is speedin service, and to obtain this, in sub-ject work, all correspondence on agiven subject must be filed together,regardless of who wrote it or at whattime it was written, so that the historyof everything that has taken place onone subject may be found in one place.
Classification of Files of the U. S. ExplosivePlant at Nitro, W. Va.By Miss J. L. Dillard
Dillard, J. L. 1919. “Subject and Classification Filing: Classification of Files in the U.S. Explosive Plant at Nitro, W. Va.” Filing: A Magazine on Indexing & Filing 3(2): 401–3. https://www.google.com/books/edition/Filing/nxFLAAAAYAAJ?hl=en&gbpv=1&pg=PA401&printsec=frontcover&dq=duplex (December 2, 2025).
ne of the chief drawbacks in using the Alpha-betic and Numeric systems in conjunction with asubject file is that in handling a large amount ofmaterial a great deal of cross referencing has tobe done, causing much extra labor and filling upthe files.
drawbacks of alphabetic and numeric systems with respect to cross referencing
utive numbers are assigned to the different sub-jects; if it is necessary to sub-divide these sub-jects, a letter of the alphabet is appended. Thus-Insurance..1 , Auto. Ins... 1-1 , Auto. Fire Ins.-1-1-a.
In the Numeric system of subject filing, consec-
A Duplex Numeric system may also be used forSubject filing, which is the using of combinationsof numbers without the decimal limitations. Adash or hyphen being used instead of the decimalmark.
advantages of duplex numeric systems over decimal systems
ll correspondence is filed under the correspond-ent's number, unless it relates to branch offices orto a subject relating to some special division ofthe correspondent's business, for which it has beennecessary to assign a separate folder. In this casethey are assigned auxiliary numbers to the mainnumber. This is known as a Duplex Numericsystem of numbering.American Express Co. 52431234 Market St. , Phila., PaNew York City, N. Y.Pittsburgh , Pa.-1-2Rochester , N. Y. -3
1002. By using the primary and secondary or duplexnumeric system (see §§ 159-163, 432-433) , the primary num-ber can be used to designate the client, each case or matterhandled for that particular client being indicated by thesecondary number, permitting the grouping of the records per-taining to a given client and his affairs in one place.
Luhmann would likely have been aware of duplex numeric systems of filing from legal and governmental filing work. It's not a difficult jump to go from client to subject matter to keep ideas bundled "in one place."
Duplex Numeric
Hudders suggests duplex numeric systems for mercantile use, architects, contractors, lawyers' correspondence and for drawings and blueprint filing.
620. Should further expansion be required, a third divisioncan be made by suffixing letters of the alphabet in rotation, e.g. :4-3 FIRE INSURANCE4-3a Losses4-3b Agents4-3c Rates4-3d Danger Zones
expanding numeric systems is quite easy
615. If the filing is started on a straight numeric basis,with the titles assigned to cover broad groups, it would be pos-sible to expand it to a duplex numeric system either in partor in its entirety if need be.
Numeric systems can be expanded to duplex num.eric systems
COMPARISON OF THE DECIMAL ARRANGEMENT WITHTHE DUPLEX NUMERIC ARRANGEMENT ( showing the possibilityof expansion in the latter that is lacking in the decimalclassification )
Notice the one-to-one correspondences between these systems.
There is a sort of artificial lack of extension, but numerically it really doesn't exist mathematically.
Method
division can be limited to 26. Although provision for a third subdi-vision can be made, it is not advisable.
The duplex numeric method of filing is designed for use when the number of primary or main subjects exceeds 10 and the second sub-
Specifically note the "is not advisable" portion, particularly with respect to N. Luhmann's practice.
DUPLEX NUMERIC SUBJECT FILING