Yassir Islam of HarvestPlus clarifies the story of orange sweet potato adoption in Mozambique:
First, the paper clearly states that there was farmer adoption of OPS and substitution for white and yellow varieties: “An average of 77% of households…were considered to have adopted OSP for cultivation, representing a 26 percentage point increase in households growing sweet potatoes from the baseline….the increase in OSP intake was largely due to the substitution of OSP for white and yellow sweet potatoes.”
Read the equally important points two and three here.