Making a demo available for your game on Xbox Live can halve its sales, according to data from the Electronic Entertainment Design and Research.

The data, presented by Schell Games CEO Jesse Schell in his DICE presentation last week, showed that while having a demo was better than nothing, and having both a demo and a trailer was better than that, by far the most sales were of games that only featured trailers.

Schell said this was an example of how plans changed player behaviour.

“When you put a trailer out, people say ‘That’s cool, I gotta try that game’,” he said.

“And then when they’ve played the demo: ‘Alright, I’ve tried that game.’

“The things with no demo, you’ve gotta buy it if you wanna try it,” he said.

An obvious conclusion perhaps, but the difference in cumulative sales is quite staggering.

XBLA game demos cut game sales in half – EEDAR data