Tehnike randomizacije i veličina klastera u klaster randomizovanim studijama sprovedenim u osnovnim i srednjim školama
Abstract
Uvod/Cilj. Formiranje grupa u istraživanjima tako da budu slične u svim karakteristikama izuzev ishoda, obezbeđuje se postupkom slučajne raspodele. Cilj ove studije bio je da ispita učestalost tehnika slučajne raspodele i njihov uticaj na postizanje ravnoteže na početku istraživanja u studijama sa grupama formiranim pomenutom metodom, koje su sprovedene u školama. Metode. Pretraživanjem bibliografske baze podataka Medline ukupan broj prikupljenih radova je bio 343, od kojih je 81 ispunilo kriterijume za uključenje u studiju. Svaku publikaciju su pregledala dva nezavisna istraživača, podaci su ekstrahovani i analizirani. Rezultati. Najčešće primenjena tehnika slučajne raspodele bila je stratifikacija koja je opisana u 28 (34,6%) studija. U studijama u kojima je primenjena prosta metoda slučajne raspodele nije bilo statistički značajne razlike u broju ispitanika i klastera kao i veličini klastera između ispitivanih grupa. U studijama u kojima su primenjene tehnike restriktivne slučajne raspodele postoji statistički značajna razlika u broju ispitanika i klastera između grupa, ali ne i u veličini klastera. Zaključak. Iako u veličini klastera ne postoji razlika između ispitivanih grupa kako na nivou celog uzorka tako i u odnosu na tehnike slučajne raspodele, trebalo bi sprovesti dodatna istraživanja na većem uzorku kako bi se utvrdio uticaj primenjenih tehnika slučajne raspodele na prisustvo ravnoteže na početku istraživanja kada je u pitanju veličina klastera.
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