possible outcomes in an particular experiment, selects certain aspects of the quantum state to be measured ([*partial information*]{}), and this bound can change in a WVA scheme, although the bound should be always above the Cramér-Rao bound. In this restrictive scenario, the use of certain polarization projections can be preferable.

The existence and nature of these different bounds might possibly explain certain confusion about the capabilities of WVA, whether WVA is considered to provide any metrological advantage or not. On the one hand, if we consider the trace distance, or the quantum Cramér-Rao inequality, without any consideration about how the quantum states are detected, post-selection inherent in WVA does not lower the minimum probability of error achievable, so from this point of view WVA offers no metrological advantage. On the other hand, in certain scenarios, the Fisher information, when it takes into account [*information about the detection scheme*]{}, can be enhanced due to post-selection. In this sense, one can think of WVA as an advantageous way to optimize a particular detection scheme.

Conclusions {#conclusions .unnumbered}
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WVA schemes makes use of linear optics unitary transformations. Therefore, if the only limitations in a measurement are due to the quantum nature ([*intrinsic 