So in some cases I find it hard to decide when someone reporting for "intentionally feeding" since his score which it is obvious (say like 0/12/3) and this reported player didn't even say a word in chat.

Usually I skip this kind of cases since idk what to decide without any good reason behind the report.

I'm really curious how you guys decide on this. Please tell me...

look for close to 30 deaths in a 25 minute or less game.

so are you saying it based on how long was the game ?

Often it is related to how many deaths more than the length of the game.

When you break 1 death per minute you're doing less than trying to participate.

Based on your 0/12/3 he's attempting to help. Consider the build after that.

Boots of Mobility are one key to look for. And if they're not an attack speed type champion Zeal/Phantom Dancers are clear signs of it as well.

Revive and teleport also end the signs. I wish rune page and mastery build were also included in these but alas must wait.

Generally I base it on the chat and build. If someone's admitting to it in chat it's obvious, and so are things like multiple Zeals, all boots, no items at all, etc. Revive/Teleport or Ghost/Teleport summoner spells are a big hint they went in intending to feed too. I do look at k/d ratio too but never consider punishing for it unless they've averaged at least one death per 2 minutes for the entire game (or more for a 20 minute game since the respawn timers are low the whole time).

Longer matches can result in a deaths being less than 1 every 2 minutes. But generally a feeder game is surrendered long before that.

Okay so sometimes yeah I do meet someone who got reported with those build the Boots of Mobility and 5 Zeals and it is very obvious for that one, but for some cases idk if they actually "tried" to help or not since their build looks normal, but their death rate is pretty high than other player.

Read the chat, look at the items and use your brain. If that doesn't work skip the case. It's not rocket surgery, people.

Most intentional feeding reports are false. (though the person may be guilty of something else.) Far too many people use this report to complain that someone did poorly.

You basically look for true feeder builds (mobo/zeal types) and chat. "I'm done, Imma feed now," for example. If there is no admission of intentional feeding, they probably aren't. You can look for how they seem to be doing in chat. "They keep turret diving me," is a sign that someone is having a bad game and getting rolled, not feeding intentionally.

These are probably the highest incident of pardons, and those guilty of it are generally either blatantly guilty, or guilty of something else in other games in the case file, which simplifies it, because you should still punish a jerk.

you obviously didn't read the first post.