Amplitude-based cuts in Inter Quartile Range in K_s band and Amplitude over error for an example VVVx tile. Top: blue points show candidates that meet IQRKs and amplitude over noise criteria. The dashed red line shows the IQRKs threshold as a function of K_s magnitude; black triangles are the control VarZoo sample. Points inside the gray-shaded region are excluded from further analysis. Bottom: histogram of the amplitude of variability over the sourceaveraged photometric error. Blue histograms are sources that passed the IQRKs cuts, and the gray histogram is the VarZoo sample. The dotted black line defines the threshold value to further consider candidates (ΔK_s/σ ≥ 10).