We conducted a comprehensive literature search in Pub Med and Psyc Info, which is updated up to January 1st 2014.
For the Pub Med search we applied a previously developed search string for psychometric studies [).
in a clinic), or other self-report measurement within a clinic, in order to retain comparability between results.
We also excluded studies on assessments through unique devices specifically developed for the study, face-to-face interviews conducted by videoconference, and interactive voice response measures by telephone.
As second inclusion step, we included only those studies that aimed at assessing psychometrics and that provided data of at least one psychometric variable.
The third and final inclusion step included studies that described instruments for assessing symptoms of common mental health disorders  unipolar depressive disorders, social phobia, panic disorder with or without agoraphobia (PD/A), agoraphobia without panic, specific phobia, generalised anxiety disorder (GAD), post-traumatic stress disorder (PTSD) and obsessive-compulsive disorder (OCD).
patients or general population), recruitment method, country in which the study was conducted, language of the measurement instrument, any subgroups the results were reported for, and amount of missing data.
The psychometrics of several pen-and-paper questionnaires have been re-examined for online use and new online instruments have been developed and tested for validity as well.
This study aims to review and synthesise the literature on this subject and provide a framework for future research.
data were collected using internet-connected devices that individuals used to fill in questions about themselves.
We excluded assessments through stand-alone devices (e.g.