Are there reliable statistics about divorce rates in Christian churches? I just read an article claiming divorce rates are much lower than commonly believed among Christians, but there are no references.

Church-Divorce-Rate-Way-Lower-than-Anyone-Thought

According to the article, it is a common belief that divorce rates are around 50% and about as high in Christian churches as in society at large.
Are there reliable statistics available for specific denominations or categories of Christians that would help us evaluate these claims?
While statistics for Christians are usually easy to establish, statistics for regular church-goers are much less reliable. This is partly because statisticians know that Americans frequently overstate their attendance at church, and partly because such statistics are often developed by people inexperienced in statistical methodologies. However, the  Barna Group, an evangelical Christian polling firm with expertise in statistical research, has published a report comparing the divorce rates for different Christian and non-Christian groups.

The report, dated 2009, found that only 33 per cent of all currently or formerly married adults had been divorced. This is a lot lower than the 50 per cent often cited, but measures a slightly different statistic. Also, a person who has been divorced more than once is only counted once, so that the proportion of marriages ending in divorce will be slightly higher than the proportion of currently or formerly married persons who have experienced a divorce. 

The margin of error given for the total sample of 5017 adults is given as 1.6 per cent, and for the 3792 adults who have been married is given as 1.8 per cent. The margins of error for individual groups, such as Catholics or born-again Christians, are not given but will depend on the number of participants in each group. 

Some basic facts: 


Catholics - only 28 per cent of all adults had been divorced.  Statistically, this is probably significant, and would reflect the fact that the Catholic religion does not recognise divorce and insists that Catholics remain married for life.
Protestants - 34 per cent of all adults had been divorced. Against an overall divorce rate of 33 per cent, this is not statistically significant.
All born-again Christians - 32 per cent. This is not statistically significant.
Non-evangelical born-again Christians - 33 per cent. This is not statistically significant.
Evangelical Christians - 26 per cent. While this looks statistically significant, only 339 evangelical Christians were interviewed, so without a larger sample not a lot can be read from this.


For comparison, we can look at people from non-Christian faiths, who were interviewed. 


Associated with non-Christian faith - 38 per cent had been divorced.
This is slightly higher than the national average, but not
statistically significant because only 197 persons were in this
group, which is too small for a sufficiently accurate estimate. A different sample could well give a quite different answer.


Similarly, the sample of atheist or agnostic participants in the survey was too small, at 269 adults, for a meaningful comparison. In this group, only 30 per cent had been divorced.

It may well be that church-going Christians have a lower divorce rate than Christians who do not attend church regularly, although on the basis of these figures this would necessarily mean that non-church-going Christians must have a particularly high divorce rate, compared with non-Christians. Another issue is whether some church-going Christians tend not to go to church after a divorce, either out of unintended, but subtle pressure from the church itself, or out of embarrassment. Any statistics that attempted to compare divorce rates between church-going Christians and non-church-going Christians must take issues like this into account.