I think this is OK because it's political science, not politics.
But I wonder if there are other countries that have open primaries like in the US. AFAIK, nearly all countries have candidates selected by the party leadership. The net effect of the primary system in the US is that the parties mean nothing, essentially. Legislators vote on their own without instruction from the party leadership. I suppose it's got its benefits and drawbacks. One problem may be that in a state where one party always wins the election, people who don't agree with that party's platform may register as members, simply because the primary is the only election that counts.