Thursday, March 6, 2014

Freshman hordes slightly more godless than ever

This article is an update to my annual series on one of the most under-reported stories of the decade: the fraction of college freshmen who report no religious preference has tripled since 1985, from 8% to 24%, and the trend is accelerating.

In last year's installment, I made the bold prediction that the trend would continue, and that the students starting college in 2013 would again, be the most godless ever.  It turns out I was right -- just barely.  The number of students reporting no religious preference increased to 24.6%, slightly higher than the previous record, 24.5% in 2011.  Of course, that "difference" is not statistically meaningful.  More valid conclusions are

1) This year's data point is consistent with previous predictions, and

2) Data since 1990 support the conclusion that the number of incoming college students with no religious preference is increasing and probably accelerating.

This analysis is based on survey results from the Cooperative Institutional Research Program (CIRP) of the Higher Education Research Insitute (HERI).  In 2013, more than 165,000 students at 234 colleges and universities completed the CIRP Freshman Survey, which includes questions about students’ backgrounds, activities, and attitudes.

In one question, students select their “current religious preference,” from a choice of seventeen common religions, “Other religion,” or “None.”

Another question asks students how often they “attended a religious service” in the last year. The choices are “Frequently,” “Occasionally,” and “Not at all.” Students are instructed to select “Occasionally” if they attended one or more times.

The following figure shows the fraction of Nones over more than 40 years of the survey

The blue line shows actual data through 2012; the red line shows a quadratic fit to the data.  The dark gray region shows a 90% confidence interval, which quantifies sampling error, so it reflects uncertainty about the parameters of the fit.

The light gray region shows a 90% confidence interval taking into account both sampling error and residual error.  So it reflects total uncertainty about the predicted value, including uncertainty due to random variation from year to year.

We expect the new data point from 2013, shown as a blue square, to fall within the light gray interval, and it does.  In fact, at 24.6% it falls only slightly below the fitted curve.

Here is the corresponding plot for attendance at religious services:

Again, the new data point for 2013, 27.3%,  falls comfortably in the predicted range and slightly ahead of the long term trend.

Predictions for 2014

Using the new 2013 data, we can generate predictions for 2014.  Here is the revised plot for "Nones":
The prediction for next year is that the fraction of Nones will hit a new all-time high at 25.8% (from 24.6%).  If so, it is likely to match or exceed the fraction of students whose preference is Roman Catholic.

And here is the prediction for "No attendance":

The prediction for 2014 is a small increase to 27.5% (from 27.3%).  I'll be back next year to check on these predictions.


1) As always, more males than females report no religious preference.  The gender gap decreased this year, but still falls in the predicted range, as shown in the following plot:
Evidence that the gender gap is increasing is strong.  The p-value of the slope of the fitted curve is less than 1e-6.

2) I notice that the number of schools and the number of students participating in the Freshman Survey has been falling for several years.  I wonder if the mix of schools represented in the survey is changing over time, and what effect this might have on the trends I am watching.  The percentage of "Nones" is different across different kinds of institutions (colleges, universities, public, private, etc.)  If participation rates are changing among these groups, that would affect the results.

3) Obviously college students are not representative of the general population.  Data from other sources indicate that the same trends are happening in the general population, but I haven't been able to make a quantitative comparison between college students and others.  Data from other sources also indicate that college graduates are slightly more likely to attend religious services, and to report a religious preference, than the general population.

Data Source

The American Freshman: National Norms Fall 2013
Eagan, K., Lozano, J.B., Hurtado, S., & Case, M.H.
ISBN: 978-1-878477-26-2     187 pages.
Mar 2014

This and all previous reports are available from the HERI publications page.