Sermons delivered in black Protestant churches in the US are nearly four times longer than sermons in Catholic churches, and evangelicals are the church-goers most likely to hear about sin, punishment and redemption, according to a new analysis.

Congregations in many historically black Protestant churches are listening to their pastors for nearly an hour. Priests in Catholic churches give sermons with a median length of less than a quarter of an hour.

The figures come from an analysis of almost 50,000 sermons that were posted online by 6,431 Christian churches across the US over an eight-week period including Easter.

The Digital Pulpit, a report published by the Washington-based Pew Research Center on Monday, found that the median length of sermons in churches of four major Christian traditions was 37 minutes.

But there were “striking differences” in the typical length of sermon in Catholic, mainline Protestant, evangelical Protestant and historically black Protestant traditions – respectively, a median of 14, 25, 39 and 54 minutes.

A computer analysis of the sermons’ content found that the word “Jesus” was used in 99% in all four traditions. The most commonly used words were simple, broadly applicable terms, such as “people, “come”, “know”, “life” and “like”.

But some words and phrases were used more frequently in the sermons of some traditions. Congregations at historically black Protestant churches were eight times more likely than others to hear a phrase including the word “hallelujah”.

“Although the word ‘hallelujah’ is by no means unique to historically black Protestant services, this analysis indicates that it is a hallmark of black Protestant churches,” the report said.

Evangelical sermons contained “a number of distinctive words and phrases relating to sin, punishment and redemption” and evangelical clergy were “three times more likely than those from other traditions to include the phrase ‘eternal hell’ (or variations such as ‘eternity in hell’)”.

But, the report added, “a congregant who attended every service at a given evangelical church in the dataset had a roughly one-in-10 chance of hearing one of those terms at least once during the study period. By comparison, that same congregant had a 99% chance of hearing the word ‘love’.”

Sermons across the four traditions were “heavily laced with scripture: 95% reference at least one book, Gospel or epistle of the Bible by name, and more than half (56%) cite particular books from both the Old Testament (also known as the Hebrew scriptures) and the New Testament (which includes the Christian Gospels) in the same sermon”.

Evangelical churches were most likely to reference a book, Gospel or epistle of the Bible by name, doing so in 97% of all sermons.

The report acknowledged that the number of churches included in the analysis was a small proportion of the 350,000 religious congregations in the US, not all of which have an online presence.