Cluster randomized clinical trials in orthodontics: design, analysis and reporting issues

Pandis, Nikolaos; Walsh, Tanya; Polychronopoulou, Argy; Eliades, Theodore (2013). Cluster randomized clinical trials in orthodontics: design, analysis and reporting issues. European journal of orthodontics, 35(5), pp. 669-75. Oxford University Press 10.1093/ejo/cjs072

Preview

Text 669.full.pdf - Published Version Available under License Publisher holds Copyright. Download (1MB) | Preview

Cluster randomized trials (CRTs) use as the unit of randomization clusters, which are usually defined as a collection of individuals sharing some common characteristics. Common examples of clusters include entire dental practices, hospitals, schools, school classes, villages, and towns. Additionally, several measurements (repeated measurements) taken on the same individual at different time points are also considered to be clusters. In dentistry, CRTs are applicable as patients may be treated as clusters containing several individual teeth. CRTs require certain methodological procedures during sample calculation, randomization, data analysis, and reporting, which are often ignored in dental research publications. In general, due to similarity of the observations within clusters, each individual within a cluster provides less information compared with an individual in a non-clustered trial. Therefore, clustered designs require larger sample sizes compared with non-clustered randomized designs, and special statistical analyses that account for the fact that observations within clusters are correlated. It is the purpose of this article to highlight with relevant examples the important methodological characteristics of cluster randomized designs as they may be applied in orthodontics and to explain the problems that may arise if clustered observations are erroneously treated and analysed as independent (non-clustered).

Interest & Impact

Downloads

128 since deposited on 28 Jan 2014
11 in the past 12 months

Citations

5 Citations in Web of Science ®
6 Citations in Scopus

Search

in Google Scholar™

Services

Actions (login required)

Edit item

Actions (login required)

Edit item