We also quantified the impact of other error sources, including geolocation errors between the map and reference data, land-cover changes between dates of data collection, heterogeneous reference samples, and edge pixels.
The information collected included study population descriptions, participant recruitment and data collection methods, reference standards, details of index tests, biases present, results (including accuracy and reliability measures and patient flow) and study quality (risk of bias and applicability).
We have decided not to go in this direction because of the great differences between the two surveys in terms of data collection and reference population.
Transcribed interviews will be reviewed by the interviewer responsible for data collection (with reference to the original recording) and transcription errors will be rectified.
At study level we will extract information on methodological characteristics of the studies, such as inclusion criteria, patient recruitment, data collection, and reference standard from publications.
Despite these limitations, this is the first study with prospective data collection from reference maternity units in Northeast Brazil and it provides a picture of care at birth for preterm infants with very low weight, which contributes substantially to infant and child mortality and influences the human development index in this region.
BDT and MV participated in the data collection and references search.
Additional details on data collection and references are provided in Supplemental Material, "Additional information about data collection".
Defining signatures as specific patterns derived from singular functional or cellular entities, signatures of highly purified leucocyte cell types [ 43] and precisely defined cellular stimulation (for example, stimulation by Toll-like receptor 2 in synovial fibroblasts [ 18]) contribute to the establishment of such a systematic data collection for referencing.
