A third of group room nights are booked outside of event-contracted room blocks in the United States, according to a recently released study.

To study the extent to which attendees book outside room blocks, researchers analyzed attendee origin data for more than 170 events that had more than 880,000 attendees between 2012 and 2015. The number of attendees ranged from 60 to more than 55,000 at the different events, which varied across market segments, location, and destinations.

Researchers also estimated that only attendees from ZIP codes more than 100 miles from the meeting location would require a guest room.

“Despite general agreement that many attendees book outside the room block, the meetings industry traditionally relies on the historical room-block pickup as one of the most important metrics to value an event,” Christine “Shimo” Shimasake, managing director of empowerMINT.com and event impact calculator at the Destination Marketing Association International, said in a statement. “This study proves that the method captures only a partial story, and it is the first of its kind to quantify just how many more overnight visitors the meetings industry is continuing to drive to destinations across the United States.”

Although the study found that on average 34.1 percent of rooms are booked outside contracted room blocks, the findings also showed a significant variation in the portion of rooms booked outside the block.

“Across the sample of events studied, the variation of the share of rooms outside the block was quite large, so it’s critical to avoid applying the every-third-room assumption across all events,” Christopher Pike, director of impact studies at Tourism Economics, which conducted the study, said in the release. “Factors including event size, facility gross square footage, market segment, and length of an event all influence the share of rooms booked outside the block, and we have a tremendous opportunity to match room demand with an event more closely.”

The research was released jointly by ASAE, the Center for Exhibition Industry Research, the Destination and Travel Foundation, Meeting Professionals International, and the Professional Convention Management Association Education Foundation.

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