() Campbell and Stanley
"Experimental and Ouasi-Experimental Dosigns for Researoh" (p. 1-12)

Abstraste
The authors are concerned vith the threats
to validity on various ezporimental designs.
They view experinontation as basic in the evolution
of knowledge. Thresto to internal and external
$alidity are defined. 'Thros pre-experimental
designs are presented and their handling of the
various threats to internal validity are examined,
Through the exsminaticn of 16 research designs in the light
of 12 threats to validity, the authors intond to provide guidanes in
the selsetion of designs that may provido "adeguate and proper data
to whieh to apply statistical procedure." (p. 1) The firat section of
their paper introduces the problem and examines three "pre-experimental"
6 desigmns.
| A vezy high value is placed on exporinentstion as ",..the only "
means for settling disputed,.." (p, 2) The suthors give it a very
basic positden in their perspective on knovledze. "(I)t is a refinžng
process superimposed upon the probabijr valusble cumulations of vise
prsctice.," (po 4) In other words, experimontatio: is a means of
testing the meaning of experience, dMivancement is characterized by
"continuous, multiple experinentabdon", They do note that we should
not expect that the results of testing rival theorlen to be unembiguous.
Biven the authors? perupsotivos, it would zeem likelj that when opposing
views are presented by those competent to state then, that they would all

be partially rit.