Objective An ever-increasing number of studies analyses the distribution, determinants and consequences of time to diagnosis and delays. Weaknesses in their reporting can impede the assessment of the risks of bias and variation and thus create a risk of invalid conclusions and counterproductive clinical and public health efforts. This study sought to assess systematically the quality of reporting of articles about time to diagnosis in paediatrics.

Design Two authors identified and analysed the quality of reporting of 50 consecutive articles assessing these intervals published from 2005 through October 2011, according to a checklist we developed of 35 items potentially associated with risks of bias and variation.

Main outcome measure Frequency of articles reporting each item.

Results Symptoms that should trigger a diagnostic procedure were reported in 28% of the articles; only two articles reported whether all patients with these symptoms underwent that procedure. Only 44% of the articles defined the beginning of the illness, 46% the date of diagnosis and 60% the distribution of time to diagnosis. Two studies met the criteria for all 11 items considered essential for assessing the risks of bias and variation in this type of study.

Interpretation This study identified many weaknesses in the quality of reporting of studies of time to diagnosis in paediatrics, especially for items potentially related to risks of bias and variation. This finding underlines the need for the development of new (or the refinement of existing) guidelines for reporting this type of study.