Church research and marketing service Faith Perceptions recently released their annual Church Index based on their Mystery Guest Program.

Similar to mystery shoppers, anonymous persons visit churches and rate them on a number of factors including music, signage, greeting upon arrival, and the children's ministry.

The index averages ratings over the past six years, with this year's report covering 2008 through 2014. During this time period, Faith Perceptions mystery guests attended over 4,000 services in 450 churches across all 50 states. The average mystery guest was female, 39-years-old, believed in God or a higher power, and did not have a church home.

Megachurches were defined as having an average of 1,000 attendees or more per week. These congregations rated the highest amongst the mystery guests. The churches received top scores in seating, the sermon, the public speaking skills of the minister, and the "availability, clarity, and thoroughness" of information available in the church's brochures and online. Megagchurces also received the two lowest scores in the index in the areas of post-service atmosphere and diversity and outreach.

Microchurches—having less than 80 attendees per week—rated the lowest overall with mystery guests. They fared poorly in the areas of community awareness, information, children/youth ministry, and diversity and outreach. The small congregations scored best in category, however, in the areas of greeting upon arrival, friendliness, and pre- and post-service atmosphere.

The combined results show that all of the churches, no matter the size, could do better in the areas of diversity and outreach. The category examines "how diverse the church is, and how it connects with its community with respect to age, socioeconomic status, gender, and various ethnicities that live in the area," according to the Church Index. "Diversity and outreach" received a "Very Poor" rating in each church size.

"Community awareness" also scored no better than "Fair" in each church size, and the mystery guests' overall experience at the churches was "Fair" as well.

In addition to the Mystery Guest program, Faith Perceptions offers training and consulting services to help churches create and maintain a hospitable atmosphere for new attendees.