Clinical Trial - Design

Design

A fundamental distinction in evidence-based medicine is between observational studies and randomized controlled trials. Types of observational studies in epidemiology, such as the cohort study and the case-control study, provide less compelling evidence than the randomized controlled trial. In observational studies, the investigators only observe associations (correlations) between the treatments experienced by participants and their health status or diseases. However, under certain conditions, causal effects can be inferred from these studies.

Under the right conditions, a randomized controlled trial can provide compelling evidence that the study treatment causes an effect on human health.

Currently, some Phase 2 and most Phase 3 drug trials are designed as randomized, double-blind, and placebo-controlled.

  • Randomized: Each study subject is randomly assigned to receive either the study treatment or a placebo.
  • Blind: The subjects involved in the study do not know which study treatment they receive. If the study is double-blind, the researchers also do not know which treatment is being given to any given subject. This 'blinding' is to prevent biases, since if a physician knew which patient was getting the study treatment and which patient was getting the placebo, he/she might be tempted to give the (presumably helpful) study drug to a patient who could more easily benefit from it. In addition, a physician might give extra care to only the patients who receive the placebos to compensate for their ineffectiveness. A form of double-blind study called a "double-dummy" design allows additional insurance against bias or placebo effect. In this kind of study, all patients are given both placebo and active doses in alternating periods of time during the study.
  • Placebo-controlled: The use of a placebo (fake treatment) allows the researchers to isolate the effect of the study treatment from the placebo effect.

Although the term "clinical trials" is most commonly associated with the large, randomized studies typical of Phase 3, many clinical trials are small. They may be "sponsored" by single physicians or a small group of physicians, and are designed to test simple questions. In the field of rare diseases, sometimes the number of patients might be the limiting factor for a clinical trial. Other clinical trials require large numbers of participants (who may be followed over long periods of time), and the trial sponsor is a private company, a government health agency, or an academic research body such as a university.

Read more about this topic:  Clinical Trial

Other articles related to "design, designs":

56th Tony Awards - The Ceremony
... Original Score, Choreography, Costume Design, Lighting Design and Scenic Design ...
Boeing 747 - Design
... For more design details, see Boeing 747-400, 747-8, and 747SP ... The Boeing 747 is a large, wide-body (two-aisle) airliner with four wing-mounted engines ...
Terminology - Process Design
... "Process design" (in contrast to "design process" mentioned above) refers to the planning of routine steps of a process aside from the expected result ... general) are treated as a product of design, not the method of design ... and executives have found the term useful to describe the design of business processes as well as manufacturing processes ...
Shea Stadium - Features - Design
... The design also allowed for Shea Stadium to be expandable to 90,000 seats (by completely enclosing the grandstand), or to be later enclosed by a dome if warranted ...
Very-large-scale Integration - Structured Design
... Structured VLSI design is a modular methodology originated by Carver Mead and Lynn Conway for saving microchip area by minimizing the interconnect fabrics area ... In complex designs this structuring may be achieved by hierarchical nesting ... Structured VLSI design had been popular in the early 1980s, but lost its popularity later because of the advent of placement and routing tools wasting a lot of area by routing, which is tolerated ...

Famous quotes containing the word design:

    We find that Good and Evil happen alike to all Men on this Side of the Grave; and as the principle Design of Tragedy is to raise Commiseration and Terror in the Minds of the Audience, we shall defeat this great End, if we always make Virtue and Innocence happy and successful.
    Joseph Addison (1672–1719)

    The reason American cars don’t sell anymore is that they have forgotten how to design the American Dream. What does it matter if you buy a car today or six months from now, because cars are not beautiful. That’s why the American auto industry is in trouble: no design, no desire.
    Karl Lagerfeld (b. 1938)

    What but design of darkness to appall?—
    If design govern in a thing so small.
    Robert Frost (1874–1963)