Previous Attempts to Debunk the Mythical Retention Chart and Corrupted Dale's Cone

Critics have been attempting to debunk the mythical retention chart at least since 1971. The earliest critics, David Curl and Frank Dwyer, were addressing just the retention data. Beginning around 2002, a new generation of critics has taken on the illegitimate combination of the retention chart and Edgar Dale's Cone of Experience—the corrupted cone. Because the corrupted cone has flared up in the literature of different fields, we tend to see a variety of firefighters trying to beat back the brush fires in their own particular fields, including teacher education, engineering education, and educational technology.