Some optimal values corresponds to points on the line (max/min), while othera are slightly more complex and might rely on critical values and differences between points etc!
- Some indices seem to underestimate
- ball
- beale
- dindex
- duda
- hubert
- mcclain (very much so)
- pseudoT2
- ptbiserial
- ratkowsky
- hubert
- scott
- sdindex
- trcovw
- Some are OK
- ccc
- ch
- cindex
- db
- friedman
- hartigan
- rubin
- Over-estimate
- sdbw
- Some are jumpy
- dunn
- hartigan
- kl
- marriot
- silhoute
- tracew