Data extraction, data collection and scores computation
An evaluation of the data extraction procedure was performed to assess
the agreement of two authors (EW and JG) on a subset of five randomly
chosen papers. Subsequently, all data were extracted by one author (EW)
using an electronic data capturing system developed using the Access
2016 desk application of Microsoft Office vers. 2010. Paper
characteristics such as publication year, journal and study design along
with the STROBE items scores were collected.
Several of the 22 STROBE items were further divided into components
defined in the STROBE explanatory article 15 . For
example, this article states for the 8th STROBE item
(method assessment): “For each variable of interest, give sources
of data and details of methods of assessment(measurement). Describe comparability of assessment methods if
there is more than one group”. In this example, three specific
sub-items in which the reporting of the features “sources of data”,
“methods of assessment” and “comparability of assessment” were coded
separately. Details regarding the 22 STROBE items and their sub-items
are reported in Supplementary table 1. A four level grading system was
used for the STROBE items and sub-items: “fully reported”, “not
reported”, “reported by citation”, and “not applicable”. “Reported
by citation” indicates that the authors referred to a citation
implicating that this contains the full reporting for that given
feature; however, we did not verify if this was the case by reading the
referenced paper.