Around 40 percent of freemium game players make in-app payments, according to research by NPD Group, with males more likely to shell out than women.

NPD Group analyst Anita Frazier said most players that make in-game payments do so within the first month of playing a game, meaning that developers should look at including features that drive a quick conversion to pay.

Games using the freemium model –  which are free to download but offer paid upgrades, such as game functionality, advanced features or content – are now played by 38 percent of the US population, according to NPD Group’s Insights into the Freemium Games Market report.

Freemium games appear to have a high retention rate, with 84 percent of users continuing to play after their initial interactions.

Women are more likely to play and stick with these types of games, while males aged between 13 and 34 are the group most likely abandon games after trying them.

Frazier said that as males aged between 18 and 34 are the traditional core gamer audience they are maybe less engaged with the simpler experience of freemium games. “At a minimum, for these gamers a freemium game would provide a different experience, like a snack versus a full meal,” she said.