In the end the study boiled down to this statement..."..., level of education was the best predictor of religious knowledge." In my opinion there is a strong correlation between education and religious knowledge. The finding that atheists and agnostics had the highest score on the 32 question survey shouldn't be surprising. These two groups tend to be more highly represented in circles of higher education. Higher education equals more exposure to teaching about different religion, where often times basic religion is taught in the context of philosophy or literary history or science.
The other problem with the way the survey is presented is the way it paints people of faith in a poor light because they don't have ecumenical knowledge. Drawing this conclusion is problematic because the questions on the survey not central questions to any people's specific faith. Is a Christian any less devout, or religious, if they don't know the religious landscape of Pakistan or the century Mormonism was founded?
However, I DO think Christians have a long way to go in learning about the core tenants of the Christian faith. For too long the church has spoon fed people like sheep on a bottle. This tendency creates weak, dependent people who are unable to articulate their beliefs and even less likely to be motivated to live by them. There needs to be a balance between mind and heart, facts and emotions. Too much of one without the other leads to trouble.