I've heard it... I've likely even repeated it. You probably have also.
"50% of American marriages end in divorce."
I found out yesterday that figure is based on the fact that the number of new divorces each year is about half the number of new marriages.
What about couples like Mayme and Clarence Vail? They've been married 83 years, and this type of "analysis" completely fails to take into account their marriage longevity, or that of those who have been married any significant length of time.
Of all Americans who have ever been married, one third have been divorced. That is still a sad figure, in my opinion. But it's not nearly as dismal as one half!
From the FRC Action Update:
One of the common myths about marriage in America is that "50% of all marriages end in divorce." But that figure is derived not from long-term analysis but from the fact that the raw number of new divorces each year is roughly 50% of the raw number of new marriages. These numbers are distorted by the fact that people with successful marriages usually marry only once, while people with failed marriages have often married and divorced multiple times. Fortunately, new data from pollster George Barna included a more meaningful statistic. Of all Americans who have ever married, only one-third have ever been divorced. This two-to-one ratio of marital success should encourage young people who may actually fear the "50-50" marriage myth. Another misconception is that a person's religion and values have nothing to do with marital success. Barna found that the percentage of people who have been divorced after marrying is lower among Catholics, evangelicals, and conservatives than it is among non-Christians and liberals. That's not to mention the fact that more born-again Christians (84%) have been married in the first place than atheists and agnostics (65%). For those just embarking on the adventure of marriage, be encouraged--your chances of making it "until death do you part" may be better than you've been told.
Here's another article with more details about the recent research.