Table 2.

Inclusion and exclusion criteria

	Included	Excluded
Topic	Safe, legal tattooing program or initiatives in prison	Prevalence studies on tattoo or associated risk factors
Types of paper / data	Quantitative health evaluations of tattooing programs, including experimental and non-experimental designs that report outcome data	Descriptive quantitative papers with no specific interventions or outcomes; purely qualitative data
Settings	Pre-trial detention settings, prisons (post-trial)	Non-detention settings
Types of publications	Papers in peer-reviewed journals, grey literature reporting on project implementation	Letters, editorials, commentaries
Language	English, French, Spanish	Papers published in other languages than English, French or Spanish
Publication date	Until 27 June 2018