title: Studies with staggered starts: multiple baseline designs and group-randomized trials.
abstract: OBJECTIVE
  Multiple baseline designs (MBDs) have been suggested as alternatives to group-randomized trials (GRT). We reviewed structural features of MBDs and considered their potential effectiveness in public health research. We also reviewed the effect of staggered starts on statistical power.
  
  
  METHODS
  We reviewed the MBD literature to identify key structural features, recent suggestions that MBDs be adopted in public health research, and the literature on power in GRTs with staggered starts. We also computed power for MBDs and GRTs.
  
  
  RESULTS
  The features that have contributed to the success of small MBDs in some fields are not likely to translate well to public health research. MBDs can be more powerful than GRTs under some conditions, but those conditions involve assumptions that require careful evaluation in practice.
  
  
  CONCLUSIONS
  MBDs will often serve better as a complement of rather than as an alternative to GRTs. GRTs may employ staggered starts for logistical or ethical reasons, but this will always increase their duration and will often increase their cost.
authors.affiliation: Centers for Public Health Research and Evaluation, Battelle Memorial Institute, Columbus, OH 43201, USA. RhodaD@battelle.org
authors.forename: Dale A
authors.initials: DA
authors.lastname: Rhoda
authors.forename: David M
authors.initials: DM
authors.lastname: Murray
authors.forename: Rebecca R
authors.initials: RR
authors.lastname: Andridge
authors.forename: Michael L
authors.initials: ML
authors.lastname: Pennell
authors.forename: Erinn M
authors.initials: EM
authors.lastname: Hade
mesh_terms: D002986:Clinical Trials as Topic / Q000379:methods*; D006801:Humans; D011634:Public Health; D016032:Randomized Controlled Trials as Topic; D012107:Research Design