Possible to set threshold of people you want to be matched against

I just played one of many games where an opponent will just leave.

In this case @hack4dor who has played 1400 games but only completed 83%.
Of course there are reason IRL to abandon a game, but doing that ~230 times? Come on.
It would be helpful to have a setting that I don't play ranked matches with players with under 95% completion rate, maybe even a site wide default. Once you go under that rating you can only play unrated until your rate goes back up.
Anyone else feel frustrated by this? Are there other ideas?

That's not how the game completion rate works. It's over a limited time, not the total of your games. Something like last 30 games, 30 days or something like that. Probably because things like connectivity and such...

Point still stands even however it is calculated, 83% is still abysmal, he's played plenty of games recently in 30 days or 30 games

I have a 93% completion rate and I never abandon games. How is completion rate calculated?

I know I do not answer the question completely but I hope this still helps: AFAIK the rate is calculated by looking back into the last 30 (or some other number) games you lost or aborted. Which of these games count as incomplete I do not know, but it is probably those that you aborted and those where you lost due to disconnection. I do not know the exact number, but it does not take your wins into account. Consequence: if you abort/disconnect/... a single game, it takes 30 (or whatever the number is) losses to get back to 100% completion rate. A completion rate of 93% means e.g. that two of your last 30 losses where considered to be not completed.

So now we understand how the completion rate is calculated, why do we have it if it cannot be used in some way? Is this even the place to bring these kind of ideas up with the devs or is this forum just a self help group for users?

Oh yes, devs read the forum and implement sensible solutions a lot.
What they usually don't do, is listen to some random person complaining about a non existing problem and implemet poorly thought out solutions.
Its the last 30 games and a game counts as aborted if it was canceled before it started, no move was made, ragequit and if I am not mistaken also letting the time run out is also included (technically a ragequit but more difficult to track)
Also @Mawk Don't name users in the forum, if there is a legit problem report them.

#1 Thanks, last year I added comments to github.com/ornicar/lila/issues/5377