Valve provides all loot boxes in Dota 2 with visible probability percentages prior to purchase. In addition to the insight that players already receive in the contents of boxes, they can now see per item how likely they are to receive the content.
In the blog post about the ‘Treasure Update’ Valve announces next to a number of new bundles also add this to. For the purchase of a lootbox, you can see which items the box contains. Next to the display of the individual item is an arrow. When players click on these, they will see a percentage that indicates the extent to which they have a chance of winning the item.
The percentages are based on the number of boxes that the player has already opened. The chance of rare items increases as more loot boxes are opened. Valve also claims to have simplified the way of calculating the odds but does not clarify what exactly has changed.
Dota 2 is not the first game to identify probability percentages for lootbox items. Rocket League of Psyonix has been applying this since July of this year on its own boxes. In addition, Apple claims that all apps in the App Store that sell loot boxes should show a clear percentage of odds.