How do I interpret Strength of Schedule?

This is probably a dumb question, but for some reason my brain is having trouble understanding how strength of schedule works, specifically, the one provided by the Ballers.

For example I see that for a full season Arizona has a QB SOS of 18 (orange), does this means that the Cardinals have the 18th hardest schedule for their QBs (aka KM)? Or, that QBs playing against Arizona have the 18th hardest schedule?

Can someone clarify please.

Thanks FootClan

the Cardinals have the 18th hardest schedule for their QBs (aka KM)

Strength of schedule is a huge asset. My strategy during the second half of the season (if it seems like I will easily make the playoffs) is to target the players with the easiest SOS during my playoff weeks for trades. Some players just dominate no matter the SOS but for everyone else, you can always sell high on some of your players by trading them for good players with great matchups. Good luck!