Two different channels, different cpm

I hardly make videos for two of my channels but somehow the CPM is way different for each of them...

My one channel has $14 CPM with like 1800 views so it so I'm getting $1.80 estimated earnings.

My other channel has about $2 cpm with 3000 views and I'm getting $1.44 estimated earnings.

Is there a reason why one is higher than the others? Do you get more cpm for less views or something. These two channels are adsense based.

Since the channels are AdSense based, the CPM can vary depending on what niche the video is in. If they're the same niche, it could just be that one channel has more reputation than the other.