Are you trying to estimate the bias depending on the type of selector used (slider, input, options, ...)?
Very interesting concept :)
EDIT, forgot to add: if this is the case, have you thought of storing the type of selector in a cookie, so that refreshing the page gives always the same type?
Yeah, I considered a more involved way of choosing the interfaces to present — the server attempts to even out the distribution of interfaces, use cookies to limit, etc — but I also just really wanted to get this made in a couple hours. The current implementation is about as simple as it gets.
Very interesting concept :)
EDIT, forgot to add: if this is the case, have you thought of storing the type of selector in a cookie, so that refreshing the page gives always the same type?