Tel. 23.029; 29.038 - Indirizzo telegrafico: Istgenetica ~ Pavia

LLCS/adm

 

ISTITUTO DI GENETICA
UNIVERSITA DI PAVIA
VIA SANT’ EPIFANIO, 14

PAVIA

Dear Gene,

I am enclosing,
of the first issue of the

23.28.1962

Dr. E. Garfield

Institute for Scientific
Infcrmation

33 South Seventeen Street

Philadelphia 3, Pa.
U.S.A.

on Joshua's request, a copy
newsletter "Taxometrics",

giving available computer programmes for analysis of
clusters in taxonomy. You can get a copy of future

letters by writing to Mr.

Hill.

I may add that 5 is a measure of similarity
between two strains (or species) and is usually the
% of characters that two strains have in common.
In the cage of our matrix, citations x cited, journals
are roughly the equivalent of strains (species), and
similarity may be taken as the % of cross citations.
However, we have to resolve the asymmetrical matrix
citing journal x cited journal into a symmetrical one
as the mtrix of S values is. Perhaps a first trial
might be made by taking as S value, say between JANA and
AJHG the averaze between the % of citations found in
JAMA which refer to AJHG papers, and the % of citations
in AJHG which refer to JAMA papers. This is not ideal
but at the moment I cannot imagine a better method. An
analysis of the actual data would certainly be useful
in this respect. The computer programme will then show
which clusters can be formed out of journals. But I am
afraid that none of the availabie programmes can hrendle

a thousand journals,

I am therefore a little doubtful, from a
superficial look at the programmes, that any of them
will be useful as such. We are likely to develop new

o/s
2. o/s

methods here, but it is hard to say how long it
will take; probably longer than desirable from your
point of view.

In the second half of September I will be
able to contact my colleagues of the Computing Center
here, who might be the best people to get in touch
with for s3eiing what prospects there are cf establi-
shing a keypunching center here, ard I will let you
know something final about it,

All the best,

Lel. Cavalli-Sforza

C/to Prof. Lederberg