I must say I agree with Jannek. I have build a fair number of suveys in my time, and what you have right now is probably scaring away potential respondants.
You could check this URL for a couple of tips on, how to build a good survey:
http://www.sciencebuddies.org/science-f ... rvey.shtml
Also, you might want to use more multiple-choice questions. That way, the responses are much easier to quantify. Right now, you are just getting a huge bunch of text-quotes. With multiple choice, it's much easier to analyse the material afterwards, as it is already quantified in the responses themselves. Also - multiple choice is much faster to fill out for the respondant. You are asking people to write everything out in words, which may also scare some potential responders away.
Don't get me wrong - I think it's super cool, that you are actually collecting real world data for a masters thesis. Not enough people do that! (IMHO)

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