The degree of Doctor of Philosophy (PhD) is usually awarded after a programme of study – which in the US can last up to eight years – leading to the production of a thesis. An earned PhD is intense, gruelling and is the gold standard in academia. You don't do it unless you're smart and dedicated, and those three letters after your name are a coveted badge of achievement.

There are also honorary degrees, awarded to people a particular institution might want to recognise. They don't have to have done any work for the award (Kermit the Frog got one from Southampton College, Long Island University in 1996) and it tends to be frowned on if they actually use their title.

But a Christian university in the US is being accused – not for the first time – of blurring the lines between the two and allowing well-known evangelical Christian leaders to claim academic honours they don't in fact possess.

Among Life Christian University's list of "distinguished degree holders" are household names such as Kenneth and Gloria Copeland, Benny Hinn and Joyce Meyer. LCU says: "It has been the privilege of Life Christian University to recognize their published works, along with their lifetime ministry achievements in consideration for earned degrees from LCU."

Life Christian University is based in Tampa, Florida, and says its objective is "to provide the highest quality spiritual education possible at the most affordable price". It offers diplomas and degrees in theology, and is accredited through a church educational organisation called Accrediting Commission International. It sits outside mainstream government accredition because "we believe we should not allow secular institutions to dictate the qualifications for instructors or the programs for a Spirit-filled ministerial degree".

What isn't quite clear from its website is that the degrees have not been "earned" for work undertaken at the university or for an academic thesis any of the holders submitted. In spite of this, author and evangelist Joyce Meyer claims on her website that she has an "earned PhD" from LCU. Hinn and the Copelands don't appear to make the same claim. All were approached to comment on this article, but none responded.

More controversially, conservative historian David Barton, a political activist with a large following among Republican-voting evangelicals, has also claimed to have an earned PhD and it appears to be from LCU. In the face of received wisdom about the foundation of the US, Barton argues that it was founded as an explicitly Christian nation. He has been widely derided by scholars and his book The Jefferson Lies was withdrawn from sale by publishers Thomas Nelson; a senior executive said that "basic truths just were not there".

Researcher Warren Throckmorton, who exposed the errors in Barton's book, noted that a video in which Barton claimed to have an earned PhD had been taken down after Throckmorton pointed out that it appeared to come from LCU; Barton has not commented, and did not return requests for clarification from Christian Today.

However, Christian Today approached LCU for comment and received a lengthy response from its president and founder Douglas Wingate. Wingate said: "It seems that questions have arisen concerning various well-known ministers of the Gospel who we refer to as Distinguished Degree holders. These ministers are not graduates of LCU but are those for whom we recognize the comparable academic work in their published teaching materials, many of which we use as texts in our university, and we have matriculated degrees for their work."

Wingate goes into detail about the credits for previous study, published work and "life experience" offered to those seeking to enrol on LCU courses. He outlines the study required for different degrees including PhDs, but says: "Again, these degrees may consist of transfer credit, and previously published works."

Christian Today asked whether Barton had a PhD from LCU. Wingate appears to imply he does, saying: "All of the candidates work is thoroughly examined before credit is awarded and it is clearly identified on their transcript. That is certainly the case with Dr David Barton, whose work in comparison to the revisionist historians, make[s] them look completely foolish."

He says later: "Some unsaved liberal academics are drastically opposed to our methods of assessment for earned degree credit, but they need only to concern themselves with their own anti-Christian and often Anti-Christ secular schools, which LCU has nothing in common with."

The implication of Wingate's statement is that the holders of LCU "earned PhDs" may not have studied at the university or submitted a thesis at all.

In response to Christian Today's question about whether LCU should change the status of the 'earned degrees' to 'honorary degrees', Wingate said "emphatically, no".

"It is simply imprudent to compare apples to oranges, and the function of ministry education institutions do not compare to the lower forms of education offered in the secular liberal arts institutions," he said. "Those institutions should simply continue doing what they do, and we will simply continue doing what we do."

Wingate is clearly convinced that LCU's 'distinguished degree holders' are doing nothing inappropriate in claimed they earned their degrees, even though an 'earned degree' in the wider academic world means something very different from what it means to LCU. But while his "apples and oranges" comparison might work if the customer is presented with a clear choice between different fruits, when the grocer tries to sell an apple as an orange to someone who doesn't know the difference, there's a problem.

Follow Mark Woods on Twitter: @RevMarkWoods