Users can abandon a survey and discard the data collected. However, when data is primarily collected through repeats (particularly when devices are offline for extended time) some users have accidentally discarded a significant amount of data they actually wanted. They report it is too easy to mistakenly choose discard when they just want to close or after an app crash. My suggestion is to make the 'discard' procedure more interactive to ensure users really want to permanently erase the data eg: clear warnings and second chances. Ideally a simple parameter would set how many hoops a user must jump through before the data goes forever.