The observable $E_g$ statistics
  Recently Moradinezhad Dizgah & Durrer have shown that the $E_g$ statistics,
useful to test theories of modified gravity, is plagued by additional scale and
bias dependent lensing contributions. In this work we develop and illustrate a
method to remove these lensing terms by using in addition to the galaxy
clustering data also shear data and the correlations of shear and galaxy
clustering. We introduce a truly observable statistics termed $\tilde E_g$
which conserves the properties of scale and bias independence on linear scales.
The method discussed here is best adapted to photometric surveys. It is found
that the corrections to the original $E_g$ statistics are small for the present
DES data, but for future surveys of the quality of Euclid they are very
substantial.
