doppelblind

Doppelblind is a term that has appeared in discussions about experimental design to describe a heightened form of blinding intended to further minimize bias beyond the conventional double-blind protocol. The word is a portmanteau of doppelgänger and double-blind, and is not widely standardized in guidelines or textbooks. In the concept's formulation, a doppelblind study would involve an additional layer of concealment: alongside the participants and primary investigators remaining blind to treatment assignment, an independent second blind assesses outcomes or interpretations, using a separate data stream or evaluation team to verify results and detect bias.

Implementation varies across proposals. Some describe two independent blinded evaluators or algorithms that code outcomes in parallel, with discrepancies escalated to a third party who is also blind. The final unblinding would occur only after consensus or predefined rules are satisfied. Proponents argue that a doppelblind approach could improve replication and reduce subtle biases arising from expectations of investigators or participants. Critics point out increased complexity, resource demands, and the lack of standardized validation; they note that existing methods such as triple-blind designs and robust preregistration already address many bias concerns.

Because the term is not part of established methodological taxonomies, its exact meaning and applicability differ by source. It remains primarily described in theoretical discussions, commentary, and some experimental design debates rather than in widely adopted practice or formal guidelines.