 Kirk W. Brown and Richard M. Ryan of the University of Pennsylvania have developed a 15-item "Mindful attention awareness scale" to measure dispositional mindfulness.The concept of Flow studied by Mihaly Csikszentmihalyi has been compared to Buddhist meditative states such as samadhi and mindfulness.Ronald Siegel describes flow as “mindfulness while accomplishing something.” Nobo Komagata and Sachiko Komagata, however, are critical of characterizing the notion of “flow” as a special case of mindfulness, noting that the connection is more complicated.