By Egil H. Lehmann and Hogne Sandvik . Department of Public Health and Primary Health Care, Division for General Practice, University of Bergen, Norway. The purpose of the present article is to show how computer simulation can enable clinicians with only a limited background of statistics to design experiments of the so-called sequential type. In ordinary, 'classical' experimentation, observations are examined when the experiment itself is finished. In sequential experiments, the observations are examined in a systematic manner as the experiment proceeds, in order to terminate the experiment at the earliest possible time.
Sequential experimentation is attractive from many points of view.
In medicine, ethical and economical arguments weight heavily in favour. Also, it is a fact of life that many experiments said to be classical are in fact of the sequential type, because researchers allow themselves informal analyses of the results before the experiment is finished. However, the majority of medical experiments are still of the classical kind. Sequential plans lead to more imprecise estimates, they may be difficult to administrate, they may not be sufficiently known, they may have gotten a reputation of being theoretically difficult. We suspect the latter.