Fig. 1

Overview on study design. The upper part (black) of the figure shows the patients collected in the kids lung register (KLR) and categorized according to the KLR algorithm between 1997 and 2012. Patients received a working diagnosis and were categorized into DPLD categories and subcategories; the latter process is described in more detail in Addditional file 2: Figure S1. The lower part of the figure (red) describes the workflow used for the re-categorization of 100 cases selected randomly and in proportion of their occurrence in the KLR. Two reviewers (AI, MG) re-assessed those cases blinded and independently and obtained a working diagnosis, categorization and sub-categorization according to the workflow in the lower part of Addditional file 2: Figure S1 (red)