A good rule to remember when designing surveys is: No one wants to answer your survey (unless they're really really mad or you are paying them). This rule is especially true for in-app surveys. People are using your app to do a job, accomplish a task, or waste time, and your need for data to prove to the Powers That Be that you and your team are doing a great job and deserve a raise is interrupting what the user wants to do. So think very carefully before implementing an in-app survey.