Comparison of photo-type classification vs. spectroscopic classification for the 189 known L and T dwarfs from DwarfArchives, as well as 111 late M stars. Classifications were computed to the nearest half spectral sub-type. Because the classifications are quantised, small offsets have been added in order to show all the points. The dashed lines mark misclassification by four spectral sub-classes. The three outliers marked by diamonds are discussed in the text.