For the first time Scientists measure real-world smartphone use.
 

With nearly two billion smartphone users worldwide, the number of publications examining the effects of smartphone use on our health and psyche has grown rapidly. Researchers argue that smartphone data can contribute a lot as a research tool in psychology, yet few use objective data, the practiced use of self-reported data has limited validity and should be accompanied by real-behavior measurements.

Researchers at the University of Lincoln analyzed the behavior of 29 participants, statistically calculated as an adequate number for finding the correlation between actual and self-reported usage, using an app to collect the data. The app recorded a timestamp when the phone became active and another to record when the phone was not used anymore. After 14 days, the participants were asked to estimate how much they used their phone on average each day (including calls and listening to music). This measure was used in subsequent analyses of subjective estimates. They were then asked to estimate how many times they use their phone each day, and finally were asked to complete the MPPUS (Mobile Phone Problem Use Scale: a questionnaire used in research to measure mobile use).

http://da.feedsportal.com/c/34563/f/...e0Euse/ia1.htm