head to head
DayZ asks more than SCUM, and the gap is variance.

Variance · Grand Arena
Hardcore survival sandbox where other players are scarier than the zombies.

Execution · Practiced Mastery
A hardcore open-world survival game where other prisoners are the real threat.
DayZ leans Variance (Grand Arena); SCUM leans Execution (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
DayZ
gunfights punish slow hands severely
SCUM
Realistic gunplay and ballistics punish poor aim
DayZ leans a little harder on reads, though the gap is small.
DayZ
every survivor met may lie, ambush, or befriend
SCUM
Human players ambush and adapt across the island
DayZ leans clearly harder on variance.
DayZ
loot spawns and who you meet are unknowable
SCUM
Loot spawns and unseen players create constant unknowns
SCUM leans a little harder on optimization, though the gap is small.
DayZ
map knowledge and survival routines compound
SCUM
Deep metabolism and gear systems reward planning
A matching score does not mean a matching test. Two games can both sit at 10 on execution and demand completely different things of you - which is why the reasoning above matters more than the number beside it.