Skip to main content

Table 4 Methods of analysis

From: The stepped wedge trial design: a systematic review

Lead Author Date Primary outcome measure Method(s) of Analysis
Gambia Hepatitis Study Group [4] 1987 Liver cancer rates/Vaccine efficacy Comparisons of incidence rates on a step by step basis to identify vaccine efficacy
Cook [17] 1996 Health Behaviour Questionnaire measures Comparison of group means and group by time, gender and education interactions (F-test)
Wilmink [19] 1999 Incidence and mortality of RAAAs Poisson likelihood distribution for incidence rates in person years and maximum likelihood rate ratios
Somerville [14] 2002 Respiratory Health Symptoms Not stated (description of intervention only)
Fairley [15] 2003 Proportion of missed doses Unpaired t-test of means
Hughes [12] 2003 Mother to child HIV transmission Not stated (protocol only)
Levy [16] 2004 Proportion of missed doses Wilcoxon rank-sum test
Priestly [22] 2004 Rate of in-hospital deaths Logistic regression Cox proportional hazard models (length of stay)
Bailey [18] 2004 Water quality Summary statistics only Time series analysis for diarrhoea rates
Grant [20] 2005 TB episodes >90 days after clinic entry Poisson random effects model
Ciliberto [21] 2005 Attainment WHZ score >-2/Death 95% CI for differences between groups Linear and logistic regression for effects of covariates
Chaisson [13] 2005 TB Incidence Step by step analysis of incidence Conditional logistic regression Cost-effectiveness analysis