You need a control if you are experimenting in some way – not sure you need one for the type of work you are doing, but you will defiantly need to consider bias in your sample – active COL members may not be totally representative of cocker owners in general! You will need some data from outside of COL I would of thought.
Among COL members you may for instance find a lower percentage of dogs coming from puppy farms, or more rescue dogs than normal or even a higher percentage of “problem” dogs – whose owners have been drawn to COL in the first place – could be a whole study in itself.
Re designing questionnaires my experience is that you always end up wishing you had asked one extra question – perhaps you could use “Dog related polls” to get some interim data – check sample size and representativeness etc.
You have probably thought of all this and more
– I used to work in research and I think I’m getting withdrawal symptoms-
Good luck.
