How to you differentiate a player about whether they are elo boosting

Ok first of all, I'm not that great player, I'm just a normal silver. Sometimes I got rekt by the opponent real hard while majority of time this is not the case. So I'm wonderting how you spot a player is elo boosting or just playing good. I just got completely dominated by a midlaner named: bootac009, and he's silver 5. His win rate is just above 50%, but recently he got a crazy win streak with some kinds of 20 KDA. So is that a elo boosting or just he suddenly plays good?