I'm having some issue overlaying 2 point graphs on a box plot. The code seems to work well when i added only one point graph. Here is the code below:
ggplot(data1, aes(x= reorder(DMU,order), y = Efficiency)) + 
  geom_boxplot() + 
  geom_point(data = data2, aes(x = dmu, y = eff, color = "eff")) + 
  scale_color_manual("", breaks = c("eff"), values = c("blue")) + 
  geom_point(data = data3, aes(x = DMU, y = eff2, color = "eff2")) + 
  scale_color_manual("", breaks = c("eff2"), values = c("red")) 
I keep getting the error below: Scale for 'colour' is already present. Adding another scale for 'colour', which will replace the existing scale. Error: Insufficient values in manual scale. 2 needed but only 1 provided.
 
    