Fong, Zaleski & Leach (2015), Journal of Positive Psychology (28 studies meta) — challenge-skill balance to flow is MODERATE; clear goals + sense of control also robust antecedents

Claim: Fong, Zaleski & Leach (2015), "The challenge-skill balance and antecedents of flow," Journal of Positive Psychology 10(5), 425-446 (28 studies meta): the challenge-skill balance / flow relationship was "moderate" — "compared to other theorized antecedents, challenge-skill balance was a robust contributor to flow along with clear goals and sense of control."

Source: Fong, Zaleski & Leach (2015), JPP.

Confidence: Verified (meta-analysis).

Why this matters for Candid: Defensible empirical anchor — challenge-skill balance is moderate, not decisive. Clear goals and sense of control are also robust antecedents and are easier to engineer into a tool.