Angus et al .
( 2015 ) have recently faulted MOND as follows : Studying thirty disc galaxies from the DiskMass survey , they derive the profiles of velocity dispersion perpendicular to the discs as predicted by MOND , call them \sigma _ { \scriptscriptstyle M } ( r ) .
These are then compared with the dispersion profiles , \sigma ( r ) , measured as part of the DiskMass project .
This is a new ( theory dependent ) test of MOND , different from rotation-curve analysis .

A nontrivial accomplishment of MOND – not discussed by Angus et al .
– is that the shapes of \sigma _ { \scriptscriptstyle M } and \sigma agree very well , i.e \eta ( r ) \equiv \sigma _ { \scriptscriptstyle M } ( r ) / \sigma ( r ) is well consistent with being r -independent ( while \sigma and \sigma _ { \scriptscriptstyle M } are strongly r dependent ) .
The fault found with MOND was that \eta is systematically above 1 ( with an average of about 1.3 ) .

I have suggested to Angus et al .
that the fault may lie with the DiskMass dispersions , which may well be too low for the purpose at hand : Being based on population-integrated line profiles , they may be overweighed by younger populations , known to have much smaller dispersions , and scale heights , than the older populations , which weigh more heavily on the light distributions .

I discuss independent evidence that supports this view , and show , besides , that if the DiskMas dispersions are underestimates by only 25 % , on average , the MOND predictions are in full agreement with the data , in shape and magnitude .

Now , Aniyan et al .
( 2015 ) have questioned the DiskMass \sigma on the same basis .
They show for the solar column in the Milky Way that : “ Combining the ( single ) measured velocity dispersion of the total young + old disc population… with the scale height estimated for the older population would underestimate the disc surface density by a factor of \sim 2. ” Or , equivalently , that the population-integrated dispersion underestimates the proper \sigma by \sim 30 \% .
If this mismatch found for the Milky Way is typical , correcting for it would bring the measured DiskMass \sigma ( r ) to a remarkable agreement with the predicted MOND \sigma _ { \scriptscriptstyle M } ( r ) .