head to head
Neither is simply harder - they are hard in different places. Sid Meier's Civilization demands more variance; The Elder Scrolls V: Skyrim demands more execution.

Optimization · Pure Optimization
Long-horizon empire optimization over a randomly dealt but mappable map.

Optimization · Pure Optimization
An open-world RPG mostly about discovering and stacking exploitable progression systems.
Sid Meier's Civilization leans Optimization (Pure Optimization); The Elder Scrolls V: Skyrim leans Optimization (Pure Optimization).
The Elder Scrolls V: Skyrim leans clearly harder on execution.
Sid Meier's Civilization
Turn-based clicking, zero physical demand
The Elder Scrolls V: Skyrim
Combat is forgiving; aim and timing rarely punish you.
Sid Meier's Civilization leans a little harder on reads, though the gap is small.
Sid Meier's Civilization
AI leaders follow mappable personalities, not adaptive minds
The Elder Scrolls V: Skyrim
Enemy AI is scripted and exploitable; not adaptive.
Sid Meier's Civilization leans clearly harder on variance.
Sid Meier's Civilization
Map generation and combat rolls hide early information
The Elder Scrolls V: Skyrim
Loot tables and leveled lists inject mild randomness.
Sid Meier's Civilization leans clearly harder on optimization.
Sid Meier's Civilization
Tech routing, expansion and economy are deeply solvable
The Elder Scrolls V: Skyrim
Skill stacking, enchant loops, and exploits are deeply solvable.
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.