What is the Callimachus numberA Callimachus' number (CN) is a way to present numerically an educated estimation of the preservation and the legibility of a papyrus, using a decimal number between 1 (highest readability, «perfect» conservation of the text) and 0.
There are two basic Callimachus numbers: Callimachus Readability Number (CRN) and Callimachus Conservation Number (CCN). CN are still in beta.
How the Callimachus number is obtainedThe information used to calculate this number comes from the TEI tags and attributes used by the partners of the Papyri.info project during the encoding of the edited text of the papyri into a digital edition (e.g. tagging a letter as «supplied»), the values of the attributes of such annotation, and some calculations about the context of each letter. This number is just one of the many ways to estimate this kind of information.
CN is always a number between 0 and 1 (one means all the text is perfectly readable).
To compute CN we count each letter detected by the editor and annotated by the annotator of the text. We asign a value between 0 and 1 to each letter, and the sum of all such values is divided by the number of letters.
The value assigned to each letter depends on: (a) it is state of preservation; (b) whether it can be used to read a word.
Callimachus Readability Number (CRN) is a measure of the
Callimachus Conservation Number (CCN) is a measure of the
The «squared» version of any Callimachus number (CRN2, CCN2, etc.) is just a way to amplify the differences between different states of preservation / reading by squaring each letter value, then obtaining the final result using the square root of the total number.
For the calculation of CRN and CCN, here is how each letter is valued.1
|State||TEI marking & context||CRN Value||CCN Value||CRN2 Value||CCN2 Value|
|visible letter, part of a word||none||1|
|unclear letter, part of a word||<unclear>||0.9||0.7||0.92||0.72|
|visible letter, not part of a word||none||0.8||0.9||0.82||0.92|
|unclear letter, not part of a word||<unclear>||0.7||0.72|
|letter supplied thanks to a parallel||<supplied> evidence=«parallel»||0.65||0||0.652||0|
|supplied letter in a gap of less than 5 letters||<supplied> reason=«lost», «undefined»||0.6||0.1||0.62||0.12|
|supplied letter in a gap of more than 5 letters||<supplied> reason=«lost», «undefined»||0.5||0.1||0.52||0.12|
|illegible letter, part of a word||«illegible»||0.4||0.3||0.42||0.32|
|illegible letter, not part of a word||«illegible»||0.3||0.32|
|«vestiges» of a letter||«vestiges»||0.25||0.2||0.252||0.22|
|illegible text; the number of missing letters can be counted||<gap> reason «illegible» @unit=«letter» @quantity||0.2||0.22|
|illegible text; the number of missing letters can be approximated||<gap> reason «illegible» @at least/ atMost||0.18||0.2||0.182||0.22|
|lacuna; the number of missing letters can be counted||<gap> reason «lost» @unit=«letter» @quantity||0.16||0.15||0.162||0.152|
|lacuna; the number of missing letters can be approximated||<gap> reason «lost» @unit=«letter» @at least/ atMost||0.14||0.15||0.142||0.152|
|illegible; number of letters unknown||<gap> reason «illegible» @unit=«line»; @extent=«unknown»||0.12||0.2||0.122||0.22|
|lacuna; near a word; number of letters unknown||<gap> reason «lost» @unit=«line», @unit=«character» @extent=«unknown»||0.1|
|lacuna; number of letters unknown||<gap> reason «lost» @unit=«line», @unit=«character» @extent=«unknown»||0|
CRN(center) and CCN(center) refers only to the «center» of the papyrus, defined as the part of the text after the first fully preserved word and before the last fully preserved word.
For the same papyri, normally CRN is equal or higher than CCN, and the «center» version of both is equal or higher than the corresponding for the whole papyri.
CRN may change as new editions introduce the result of fresh conjectures. CCN might vary somehow, mainly as new techniques allow papyrologists to discover more text than was previously available to researchers.
1. This coefficient was revised 12.02.2021↩
❧This database and the code used to create & publish it are supported by project PGC2018-096171-B-C21 from Spain's Ministerio de Ciencia, Innovación y Universidades.