Table 2

Examples of (mis)matching causal and non-casual statements found in the objectives and conclusions sections of abstracts of observational studies published in The BMJ in 2018

Abstract conclusions
CausalNot causal
Abstract objectivesCausalConsistent
‘…assess the effectiveness of…’and ‘Little evidence was found of a direct impact of…’
‘…benefit of … in reducing … risk’ and ‘… is an overlooked risk factor for …’
Inconsistent
‘…evaluate safety of…’ and ‘…associated with…’
‘…analyse the effect of…’ and ‘…associated with…’
‘…critical determinant…’ and ‘…associated with…’
Not causalInconsistent
‘…association with…’ and ‘…is safe…’
‘…association with…’ and ‘… had no substantial effect on long term survival…’
‘…association with…’ and ‘…tackling all these risk factors might substantially… ‘
‘…association with…’ and ‘Systematically addressing … may be an important public health strategy to reduce the incidence of’
Consistent
‘To describe trends in…’ and ‘…rates were high during the study period of … with the highest rates in … vs …’
‘To assess how often …’ and ‘One in … adults … were …’
‘To develop and validate a set of practical prediction tools that reliably estimate the outcome of…’ and ‘…prediction models reliably estimate the outcome…’