formr: A study framework allowing for automated feedback generation and complex longitudinal experience sampling studies using R.

Open-source software improves the reproducibility of scient ific research. Because existing open-source tools often do not offer dedicated support for longit udinal data collection on phones and  computers, we built formr, a study framework  that enables researchers to conduct both simple s urveys and more intricate Studies. With automated email and text message reminders that can be sent according to any schedule, longitudinal and experience-sampling studies become easy to implement. By integrating a web-based application programming interf ace for the statistical pro gramming language R via OpenCPU, formr allows researchers to use a familiar programming language to enable complex features. These can range from adaptive testing, to graphical and interactive feedback, to integration with non-survey data sources such as self-trackers or online s ocial network data. Here we showcase three studies created in formr: a study of couples with dyadic feedback; a longitudinal study over months, which included social networks and peer and partner ratings; and a diary study with daily invitations sent out by text message and email and extensive feedback on intraindividual patterns.