Objectives: To investigate the extent to which cluster sizes vary in stepped-wedge cluster randomised trials (SW-CRT) and whether any variability is accounted for during the sample size calculation and analysis of these trials.

Setting: Any, not limited to healthcare settings.

Participants: Any taking part in an SW-CRT published up to March 2016.

Primary And Secondary Outcome Measures: The primary outcome is the variability in cluster sizes, measured by the coefficient of variation (CV) in cluster size. Secondary outcomes include the difference between the cluster sizes assumed during the sample size calculation and those observed during the trial, any reported variability in cluster sizes and whether the methods of sample size calculation and methods of analysis accounted for any variability in cluster sizes.

Results: Of the 101 included SW-CRTs, 48% mentioned that the included clusters were known to vary in size, yet only 13% of these accounted for this during the calculation of the sample size. However, 69% of the trials did use a method of analysis appropriate for when clusters vary in size. Full trial reports were available for 53 trials. The CV was calculated for 23 of these: the median CV was 0.41 (IQR: 0.22-0.52). Actual cluster sizes could be compared with those assumed during the sample size calculation for 14 (26%) of the trial reports; the cluster sizes were between 29% and 480% of that which had been assumed.

Conclusions: Cluster sizes often vary in SW-CRTs. Reporting of SW-CRTs also remains suboptimal. The effect of unequal cluster sizes on the statistical power of SW-CRTs needs further exploration and methods appropriate to studies with unequal cluster sizes need to be employed.

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5695383PMC
http://dx.doi.org/10.1136/bmjopen-2017-017151DOI Listing

Publication Analysis

Top Keywords

cluster sizes
40
sample size
20
size calculation
16
cluster
13
unequal cluster
12
variability cluster
12
sizes
10
stepped-wedge cluster
8
cluster randomised
8
randomised trials
8

Similar Publications

Article Synopsis
  • Identifying influential nodes in networks is crucial for understanding their structure and function; however, the traditional VoteRank algorithm has limitations in accuracy and tends to overlook network topology.
  • This paper introduces a new algorithm called Edge Weighted VoteRank (EWV), which improves upon VoteRank by incorporating node attributes and the weight of edges, drawing inspiration from human voting behavior to better assess node attractiveness.
  • The EWV algorithm not only enhances accuracy but also tackles the issue of clustering among influential nodes, demonstrating superior performance in experiments across 12 real networks compared to seven other algorithms.
View Article and Find Full Text PDF

Epithelial tissues in vitro undergo dynamic changes while differentiating heterogeneously on the culture substrate. This gives rise to diverse cellular arrangements which are undistinguished by conventional analysis approaches, such as transepithelial electrical resistance measurement or permeability assays. In this context, solid substrate-based systems with integrated electrodes and electrochemical impedance monitoring capability can address the limited spatiotemporal resolution of traditional porous membrane-based methods.

View Article and Find Full Text PDF

The smoky brown cockroach, Periplaneta fuliginosa, is a peridomestic pest inhabiting broad regions of the world from temperate to subtropical zones. In common with other related species such as the American cockroach, Periplaneta americana, female-emitted sex pheromone components, named periplanones, are known to be key volatiles that elicit long-range attraction and courtship rituals in males. How periplanones are processed in the nervous system has been entirely unexplored in P.

View Article and Find Full Text PDF

Aim: We sought to assess the effectiveness of using a breast pump for nipple stimulation to promote breastfeeding in the early postpartum period after c-section in women with full-term infants.

Methods: Selection criteria were individual and cluster randomized control trials and quasi-randomized control trials that compared using a breast pump combined with standard care to promote breastfeeding in the early postpartum period after c-section with standard care. In this systematic review, guided by the Cochrane Handbook, we conducted comprehensive searches across databases such as Medline, Embase, CINAHL, Cochrane Library, and PsycINFO (Search: April 22, 2024).

View Article and Find Full Text PDF

Control of Permanent Porosity in Type 3 Porous Liquids via Solvent Clustering.

ACS Appl Mater Interfaces

January 2025

Geochemistry Department, Sandia National Laboratories, Albuquerque, New Mexico 87123, United States.

Porous liquids (PLs) are an exciting new class of materials for carbon capture due to their high gas adsorption capacity and ease of industrial implementation. They are composed of sorbent particles suspended in a nonadsorbed solvent, forming a liquid with permanent porosity. While PLs have a vast number of potential compositions based on the number of solvents and sorbent materials available, most of the research has been focused on the selection of the sorbent rather than the solvent.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!