(study type) The nature of the investigation or the investigational use for which the study is being done.

(study design) A plan detailing how a study will be performed in order to represent the phenomenon under examination, to answer the research questions that have been asked, and defining the methods of data analysis. Study design is driven by research hypothesis being posed, study subject/population/sample available, logistics/resources: technology, support, networking, collaborative support, etc.

(study design) Plan for the precise procedure to be followed in a clinical trial, including planned and actual timing of events, choice of control group, method of allocating treatments, blinding methods; assigns a subject to pass through one or more epochs in the course of a trial. specific design elements (e.g., crossover, parallel, dose-escalation) [Modified from Pocock, Clinical Trials: a Practical approach] See Trial Design Model. See also, arm, epoch, and visit.

A plan for collecting and utilizing data so that desired information can be obtained with sufficient precision or so that an hypothesis can be tested properly.