The Phases of a Study

The term phase(s) of a study is used at various places in the OECD Principles however, this term was not defined in the Principles and its use has given rise to questions about its meaning, its applicability, and indeed its value in the context of GLP. Even though a definition for this phrase is lacking in the Principles themselves, the term has to be dealt with in this section on definitions, since a clarification of its meaning should be of some importance for the discussion of various other issues in the application of GLP, and since there is now a definition in the OECD Consensus Document on Multi-Site Studies (OECD No. 13, 2002). 

In a colloquial sense it may be well understood what the term phases of a study should signify, namely any clearly and logically delimited parts or portions into which a study may be subdivided. Such divisions can be performed in various ways, either by temporal associations, or by defined activities. The difficiilties with this term therefore do not stem so much from any problems with subdivisions of a study, but from the (not defined, thus unexplained) dual use of the word in the text of the Principles as well as in some of the Consensus Docimients. 

There is for instance the possible division of a study into a preparatory phase, followed by the experimental phase finally, the reporting phase concludes the process. The experimental phase may then be subdivided further, according to the nature of the study itself. In a field study, for instance, a logi- 

When the definitions of Test Site and Principal Investigator mention this term in the context of the location(s) at which a phase(s) of a study is conducted and the defined responsibility for delegated phases of the study , it should be clear that this with the term delegated phase one of the gross subdivision of a study, as exemplified above, is addressed. 

For the purpose of following the Principles of Good Laboratory Practice it must be recognised that the term phase of a study may be applied to two different levels of study conduct. It may be connected with the gross divisions of a study which follow the time course of study development, but it may also be used to denote single activities within the experimental conduct of a study. They are furthermore directed towards two different areas of study conduct and study control. 

---

It has to be observed at this point, that, in a very unobtrusive way, with this definition of the Principal Investigator a term has been smuggled into the GLP Principles which could give rise to difficulties in the interpretation of other requirements. This term, the phase of a study, has not been defined in the Principles, and thus had become very much open to the need for interpretation. Although the term has subsequently been defined in the OECD Consensus Document on Multi-Site Studies (OECD No. 13, 2002), it will be specifically dealt with in section 2.10 (see page 97). 

---