randomized controlled trial - those {patients} entering the trial should be allocated to their respective groups by means of random numbers, and one such group (controls) should have no active treatment
Katsete objektiivsust aitavad tagada eeskätt kaks tingimust: esiteks tuleb rakendada nn. kahekordse pimekatse põhimõtet ja teiseks tuleb katseid läbi viia randomiseeritult. Kahekordset pimekatset kasutatakse tegelikult just ravimkatsetes. On täiesti ilmne, et arst eelistab mingit konkreetset ravimit teisele. Kahekordse pimekatsega püütakse niisugust subjektiivsust kõrvaldada - ei arst ega patsient tea, millise nimetuse taga milline ravim on. Seega ei saa patsiendi raviarst antud juhul kuidagi olla teadusuurija. Samas on selge, et raviarstidega arutatakse siiski katse põhjendatust. Selline teatud mõttes eelvalik muudab aga küsitavaks randomiseerituse rakendamise, mistõttu on avaldatud arvamust, et ükski kliiniline katse ei saagi olla tõeliselt randomiseeritud.
The particulars supplied shall take the following form: ...
(c) details of the trial protocol giving a description of the methods used, including methods of randomization and blinding, details such as the route of administration, schedule of administration, the dose, identification of trial animals, species, breeds or strains, age, weight, sex, physiological status ...
intervention study - a comparison of the outcome between two or more groups of patients that are deliberately subjected to different regimes (usually of treatment but sometimes of a preventive measure, such as vaccination). Wherever possible those entering the trial should be allocated to their respective groups by means of random numbers, and one such group (controls) should have no active treatment (randomized controlled trial). Ideally neither the patient nor the person assessing the outcome should be aware of which therapy is allocated to which patient (blind trial), nor should the doctor responsible for treatment (double-blind trial), and the groups should exchange treatment after a prearranged period (cross-over trial).
