Does Stack Overflow's reputation reflect current expertise or a historical archive?

Reputation and Expertise

The Stack Overflow reputation system is designed to reward community contributions through votes and badges, yet the way reputation changes over time raises an unresolved question: does the displayed score truly represent a user's current level of expertise, or is it simply a cumulative record of past activity?

Reputation can increase via upvotes and badge grants, but it also decreases through downvotes and the occasional reputation ceiling that slows growth for high‑scoring users. These mechanics create a tension between a static historical archive and a dynamic measure of ongoing skill.

Understanding this tension is critical for users who rely on reputation to gauge expertise when seeking collaborators or hiring. The uncertainty lies in how reputation decay, badge triggers, and the ceiling interact to shape the perceived expertise of a profile over time.

What factors influence the rate at which reputation decays after downvotes?
How does the reputation ceiling affect high‑reputation users’ ability to gain additional points?
Can the reputation system be reconfigured to better reflect a user’s current expertise?