This is a question that a purchasing professional must ask themselves. After all, The Instutute of Supply Chain Management is the purchasing non-profit organization and has some fine educational and Certification Programs. I myself am a C.P.M., so I know whereof I speak. My answer to this question is that APICS is definitely a complementary source of knowledge that is keenly intertwined with the procurement knowledge offered by ISM. I have had many purchasing professionals in my classes over the years and they have benefited from the training and concepts put forth by APICS.
The view that ISM and APICS are competitive providers of the same training is, in my opinion, a dangerous and outdated one. In this age of cross-functional teams and collaboration we cannot afford to see ourselves only as skilled experts, but as skilled generalists as well. If you wish to talk more about this, please contact me at the e-mail address below.
Ron Althaus CFPIM,CIRM,CSCP,C.P.M.