OK. I just skimmed the article by @azircoin. The very simplified take home.

KE = Author Rewards + Curation Rewards/Held HP

KE = 1.0, you hold exactly as you earn (approximately!)
KE > 1.0, you hold less than you earn
KE < 1.0, you hold more than you earn

Read the analysis and reasoning here:

@azircon/top-1000-hive-stakeholders-moments-of-pleasure-years-of-pain