Informal workplace learning is a multifaceted construct. According to the octagon model of informal learning, this includes, for instance, learning by doing, reflection, and feedback.  How can this variety be measured validly with a questionnaire scale? Together with his co-authors Dr. Michael Knappstein, Prof. Dr. Niclas Schaper and Dr. Andreas Seifert, Dr. Julian Decius has published an article on measuring informal workplace learning with an economic 8-item short scale in the journal "Human Resource Development Quarterly" (HRDQ). The scale is open access and license-free for use available here.
The basis for the new scale development was the comprehensive 24-item scale that Dr. Julian Decius and his author team had also published in HRDQ in 2019.