The definition of the terms are even more subjective than what you describe. The Conservative Party of Canada is [a little bit to the political left][1] of the United States' Democratic Party.

To answer your question, usually social scientists and pollsters let people describe themselves as liberal or conservatives. Do the same: **if you need to you talk about liberals, moderates, or conservatives, be clear you talk about people who self-describe as such.** Also mention the country you're talking about. A very large segment of the site's population come from outside of the United States. Take a look at [the top users][2] and you'll see what I mean. This is not an American website.

I have an even better advice, though: don't use those terms. If you need to describe the group that espouse a belief, you're most likely (but not necessarily) doing it wrong. You don't need to say "liberals are more likely to support minimum wage" to ask [whether increasing the minimum wage increase unemployment][3]. Most questions are about facts, not affiliations.


  [1]: http://www.dangardner.ca/index.php/articles/item/91-harper-conservatives-more-canadian-than-conservative
  [2]: https://skeptics.stackexchange.com/users?tab=reputation&filter=all
  [3]: https://skeptics.stackexchange.com/questions/599/minimum-wage-and-employement/600#600