Not just be the goals scored. Obviously goals scored are the first thing but the quality of the goals(finishing), positional play, link-up play, passing and assists should all be taken into consideration. For all i know, a midfielder could play the game of his life and create chances for the striker for him to simply tuck 'em in. That might check the positioning box but that doesn't make him the better player than the midfielder. A striker needs to check all the boxes for him to have a good game.