Correction: BMC Med Res Methodol 21, 273 (2021)

https://doi.org/10.1186/s12874-021-01474-9

Following publication of the original article [1], the authors reported an error located in the funding section. The following statement “This article is co-financed by Fondo Europeo de Desarrollo Regional (FEDER)” was missing.

The original article [1] has been updated.