There is a book that taught me a great deal: Systematic Trading by Rob Carver. In it, he notes that betting/investing at the Kelly criterion implies you are qu

There is a book that taught me a great deal: Systematic Trading by Rob Carver. In it, he notes that betting/investing at the Kelly criterion implies you are quite confident in your abilities to forecast. For a margin of safety, invest less, say, half-Kelly. That way, you allow for unknown-unknowns.