ABSTRACT
I. INTRODUCTION It has been estimated that the pharmaceutical industry as a whole con ducts or contracts for about 72-84 long-term carcinogenesis screens each year, with each study costing from 2 to 8 million dollars (1). This large expenditure makes it prudent to conduct each study in a manner as efficient as possible. Study design, therefore, is an extremely important component of the overall process of conducting these studies.
