It would be an interesting study to look at the relationships of those who aren’t married but are living together.
However, if you take ONLY those who are married and compare them with each other, and one group is divorcing more than the other group, it’s not because of what non-marrieds are doing.
If I compare dogs in one area with dogs in another area, it doesn’t really matter what cats are doing.
If I compare dogs in one area with dogs in another area, it doesn’t really matter what cats are doing.
But the point of the study is: Conservative protestants are more likely to get divorced. But that is because they are also more likely to get married. So whether they include shack ups or not in the study is really an issue (although it would be intersting since the left is always trying to redefine marriage). But the study is clearly flawed, and it's conclusion is foregone due to the methodology.
Actually, I disagree with you. If two groups are identified, and one of them has a significantly lower percentage of participation in marriage (due to out-of-marriage cohabitation or “shacking up”), then the probability of higher divorce numbers in the married population naturally shifts toward the group with the higher marriage participation rate. Because the activity being studied is avoided by a significant population in the one group, there is a natural tendency for marriages in that group to be between individuals who are more committed to each other.
After all, they have taken an extra step in commitment - one which is not seen as a prerequisite for a “relationship” in their societal norms.
In the first group, there are no valid numbers for the level of relationships that form and dissolve (it’s not tracked, and shouldn’t be). In the second group, with higher marriage rates, there are valid numbers because marriage is registered with the state, as are divorces.
Early marriage could be a factor in pushing the second group’s divorce numbers higher, as well. While group 1 is shacking up, group 2 is tying the knot. To have a valid comparison, one has to study age bands with respect to the longevity of their relationships - not just marriage. Of course, some correction for uncommitted relationships via cohabitation or shacking up would have to be made.
The selection of data can bias the results of the study. In this case, by excluding without well-explained, sound scientific reasoning a large group of potential subjects, the study uses a selection bias to push its conclusions toward the idea that conservatives divorce more often.
The correct question is whether conservatives or liberals dissolve committed relationships more often. Unfortunately, I suspect there is not valid data about the rate of committed relationships amongst unmarried individuals (absent a scientifically valid survey).
Consider it this way: If I did a study of attitudes toward the Pope, would asking questions to Roman Catholics only change the results over asking questions from all congregants of all denominations? Would making the second group be all people, regardless of church affiliation or lack thereof make a difference?
In the cat/dogs counterexample you cite, the basis of this study is more like studying dogs who have owners (in conservative areas) versus all dogs (including strays) in liberal areas. The basis of the study biases the results.
That depends on who the non-marrieds are doing it with...