Churches across the Midlands are being checked by "mystery worshippers".
Churches in Telford scored highly with the mystery worshippers
The 13, normally paid to inspect stores while posing as ordinary shoppers, report on issues such as sermons, music and the warmth of welcome.
They have been hired by the Heart of England Christian Resources Exhibition (CRE).
Five churches in Telford, Shropshire, have so far been rated by the mystery shoppers, none of whom are regular church-goers.
The idea of the visits on 13 January is to find out how people's needs can be better met by churches in the region.
Benita Hewitt, from the Christian Research Association which is organising the study, said: "Although the churches in Telford were given no advance warning, several scored more than 90%, with two achieving 100%.
"Most of our mystery worshippers were genuinely surprised by the warmth of their experience in church and some were even keen to go back for more."
Churches in Telford visited by the team were; St Mary and St Leonard, Wellington Methodist, Telford Christ the King, St Matthew Telford and Union Free Telford.
The CRE, which is described as the church equivalent of the Ideal Homes Exhibition, is sponsoring the pilot programme.
The exhibition will take place at Telford International Centre from 21 to 23 February 2008.
Steve Briars, CRE event director, said: "The project in Telford, and especially Mystery Worshipper in the Midlands on Sunday 13 January, will help us monitor where there are needs in churches."
Anglican Bishop of Shrewsbury, the Right Rev Alan Smith, has welcomed the research.