Prospect rankings are arbitrary.
For one, the most heralded national experts rely typically on second-hand knowledge, research and a little observation to make their judgments about thousands of players nationally. Often local writers devoted to prospect watching provide rankings that are just as vital and respectable, since they’re focusing on just one team, not 30.
But that aside, rankings are just rankings. Often – for example – a player ranked a team’s 20th-ranked prospect finds a route to the majors and provides value a team’s third-ranked prospect will never accrue. Just look at the Phillies over the years – in a random exercise I queued up John Sickels, who does a great job writing about prospects at Minor League Ball, and his 2012 Phils pre-prospect rankings.