We are so often asking people to do research for very little incentive, and asking about very low interest topics and with online research in particular, this can lead to very casual answering approach where people don't really care what they say. People who are not buying into the reasons why you want to do the research then don't care about the answers they give.
In the research we have conducted we have found that if you can work out how to build a bond with respondents at the outset of a survey you can significantly increase participation levels and the quality of feedback and the improvements can be quite dramatic. In experiments we have witnessed 2 fold, 3 fold, even 6 fold improvements in responses simply by priming people in the right way when they start a survey, and using the principals behind Greek rhetoric to establish Ethos with respondents is one of the most effective ways of doing this.
So how did Aristotle recommend you go about establishing Ethos?
Well it is all about establishing a bond with the listener and there are lots of ways he explained this could be done.
The key thing he espouses is openness - "readiness to reveal things that one might be expected to conceal or a promise to tell the whole story from the beginning". If you think about this from a survey point of view we often hide the motives for doing a piece of research from respondents. Yet in so many cases the reason you are doing the research in the first place is to try and make better products or improve services which if explained well can be used to motivate respondents to do a survey.
Here below is an example of this technique in action. We did an experiment asking people to tell us what they think of baby wipe and with a test cell we added this message below. This had a quite measurable impact, respondents who saw this image spent nearly 50% more time answering the question.
and Laying claim to shared values: "by laying claim to certain beliefs which agree with accepted social values a speaker can with contrived inadvertence reveal something of his character" . An example of this can be seen in the fantastic market research episode of Mad Men in season 4 when the character Fey Miller went to the length of changing her entire outfit, hairstyle and make up and removed her wedding ring to interview a group of secretaries so she came across as one of them. You can transpose this thinking to the very design of a survey to appeal to a particular target audience, if you want women to talk candidly about a topic it may be an idea to dress a survey up like it were a woman's magazine for example.