Online Games to Help Canadian and U.S. Adults Identify COVID-19 and Vaccine Misinformation: three Sequential Randomized Studies

This protocol comprised three sequential randomized controlled studies evaluating digitaleducational interventions to counter COVID‐19 misinformation, conducted under a singleIRB approval (University of South Carolina, Pro00099400) with study specific amendments.The University of South Carolina Institutional Review Board determined the study to beexempt before participant enrollment. A fourth study in the research program, conductedunder a separate IRB approval (Pro00122534), is registered separately. Study 1 enrolled anational non‐probability online panel sample in Canada (Nanos Research); Study 2 enrolleda U.S. MTurk sample on general COVID‐19 misinformation; Study 3 enrolled a U.S. MTurksample on vaccine misinformation. This record registers the three completed trialsretrospectively. All three trials used the same intervention platform: a true/false quizover circulating misinformation items, each response followed immediately by item‐levelrefutational feedback (correct answer plus brief evidence‐based explanation) embedded ina gamified interface (points, ranks, response‐contingent feedback).Trial 1 (Canada, N = 2,018; non‐probability online panel fielded by Nanos Research,December 4‐14, 2020; general COVID‐19 content, 6 items): both arms received identicalquiz‐and‐game content; arms differed in timing of the knowledge assessment within thesingle session (in Control assessed before playing, in Game immediately after).Trial 2 (United States, N = 822; Amazon Mechanical Turk, November‐December 2020; generalCOVID‐19 content, 19 items): Game versus active‐text control receiving the identicalrefutational content as a static text.Trial 3 (United States, N = 797; Amazon Mechanical Turk, November‐December 2020;vaccine‐specific content, 17 items): same two‐arm design as Trial 2.All trials were single session. Knowledge accuracy was the primary outcome; vaccinationintention was secondary. Data quality exclusions were applied at analysis: item‐levelmissingness on the knowledge scale (Trial 1) and duplicate/non‐U.S. IP screening plus, inthe Game arm, completion code validation (Trials 2 and 3).