This podcast—Episode 3 in the series examining the validity of foot orthotic prescription variables—considers the Blake Inverted Technique, introduced in 1986 as a modification of the Root functional foot orthosis protocol to provide greater “control” of excessive pronation. Together with the proposed 5:1 cast inversion-to-calcaneal correction relationship, the technique has been widely incorporated into clinical practice and commercial orthotic manufacture. Yet, for 40 years, neither the expected control of dynamic calcaneal eversion nor the proposed geometric dose-response has been convincingly validated. Research suggests that inverted orthoses can redistribute plantar pressure and alter joint kinetics, but studies demonstrate that they do not reliably control calcaneal motion in the manner originally proposed, nor that greater inversion produces proportionately greater correction. The Blake technique is therefore used as a broader case study of how a plausible clinical hypothesis can become established orthotic convention before its defining biomechanical mechanism has been adequately tested. The episode argues for an evidence-based approach to orthotic prescription that distinguishes manufacturing precision from biomechanical precision, clinical effect from mechanistic validation, and professional authority from scientific evidence.