reasons for the discrepancy are non-linear effects, scale dependence of the biasing, poorly understood errors and/or problems with the data. However, attempts to evaluate their impact have so far failed to explain the discrepancy. In general, velocity-velocity comparisons are considered more robust as they depend more on redshift data, while density-density comparisons uses less reliable peculiar velocity data.

Recently, a new attempt to carry out a density-density comparison has been made using the SEcat catalog mentioned earlier and the UMV method to reconstruct the 3-D velocity and density fields. These reconstructed fields were then used to determine the value of $\beta$ from direct velocity-velocity and density-density comparisons with the corresponding fields predicted from the redshift survey[@secat]. Figure \[fig:umv\] shows the results of the density-density (left) and velocity-velocity (right) comparisons, which give $\beta_I=0.56 \pm 0.1$ and $\beta_I=0.51 \pm 0.05$, respectively. This result is remarkable since it is the first time a good agreement is found for $\beta$ values derived from these two methods. This encouraging new result, which apparently resolves a long-standing dispute, may be due either to the new method used in the reconstruction of the fields or to the more homogeneous peculiar velocity data used or a combination of 