I think a survey of 10-15 minutes is prohibitively long. This will certainly give you a biased sample. I'm sure many people (including me) would be happy to help you, but the cost should be reasonable, especially since there is no direct incentive (obviously there are long-term incentives, but they don't work as well when I have to do something now).
I think a survey of 10-15 minutes is prohibitively long. This will certainly give you a biased sample. I'm sure many people (including me) would be happy to help you, but the cost should be reasonable, especially since there is no direct incentive (obviously there are long-term incentives, but they don't work as well when I have to do something now).