If the other side disagrees with your calculation of lost wages, it’s up to the jury to decide. The jury looks at all of the evidence to determine whether to award you lost wages and how much you deserve.
Florida’s Third District Court of Appeal ruled in 2013 that there’s no specific evidence that you have to present for the jury to award lost wages. In the Maggolc v Roberson case, the court ruled that the jury can award lost wages as long as you show your losses to “reasonable certainty.” The court also said that the burden for proving your lost wages is lower than the burden to prove that the defendant caused your injuries.